South Africa Clay Brick Sector Energy Efficiency Guide, 2016 1
South Africa Clay Brick Sector Energy Efficiency Guidelines
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 20162 3
In the context of rising energy prices and governmental drivers to address climate change, energy
efficiency is an imperative for industry. By reducing energy use and addressing the demand side of the
equation, it is possible to reduce energy bills, make the energy system more sustainable, and have a
positive impact on greenhouse gas emissions.
As a key player within the South African industrial landscape, the brick sector can show real leadership
in driving the adoption of energy efficiency best practices.
Through the Energy Efficient Clay Brick Project (EECB), funded by the Swiss Agency for Development
and Cooperation (SDC), Swisscontact has been working with the clay brick sector in South Africa
since 2009, with the aim of reducing energy use across the approximately 100 industrial clay brick
manufacturing plants in South Africa. As part of the work, Swisscontact elected to develop an Energy
Efficiency Guideline as a reference tool for operators in the industry. The guideline compares South
Africa’s brick sector energy performance with international benchmarks, and aims to develop a better
understanding of thermal energy flow inside brick kilns and identify best practices and business cases to
help the industry to deploy the necessary measures.
Many institutions and individuals have supported the development of these guidelines and we would like
to acknowledge their contribution. They include our funding agency, SDC, the Clay Brick Association, a
number of brick manufacturers, the Department of Energy, the Department of Environmental Affairs, the
Carbon Trust, National Cleaner Production Centre (NCPC), and a number of local consultants, including
John Offerman, Oliver Stotko, Moses Motaung and Chris Dickinson.
The EECB Project will continue to work with the sector to support the implementation of best practices
and new technologies. We hope manufacturers and other stakeholders who work with them, find these
guidelines and the accompanying thermal tool helpful, as they think about future energy efficiency
deployments.
John Volsteedt, Project Manager
Energy Efficient Clay Bricks
Foreword
This study was undertaken by Clay Brick Association -
representing the brick makers that participated and contributed to the development of
the guidelines, and who should ultimately take ownership of the guidelines.
Published: June 2016
www.claybrick.org/energy-efficiency-guidelines
This study was funded by the Swiss Agency for Development and Cooperation (SDC) as part of the
Energy Efficient Clay Brick (EECB) project implemented in South Africa by Swisscontact.
Funded by:
In Collaboration with:
Commissioned by: Developed by:
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 20164 5
Table of Contents Table of Contents1. Introduction
1.1. Background and Objectives of the Project 9
1.1.1. Energy Efficient Clay Bricks (EECB) Programme 9
1.1.2. The Importance and Challenges of Energy Efficiency 9
1.2. Key Stakeholders 11
1.3. Activities Currently Undertaken by Other Organisations 11
2. The South African Clay Brick Sector 12
2.1. Typical Clay Brick Production Methodology and Product Variations Across The Sector 12
2.2. Brick Sector Production Levels and the Construction Industry 15
2.3. Breakdown of Kiln Technologies and Number of Sites 16
3. Benchmarks 18
3.1. Introduction 18
3.1.1. Continuous Kiln Benchmarks 24
3.1.2. Advantages and Disadvantages of the Main Brick Kiln Types 24
4. Performance of the Sector 25
4.1. Where is Energy Used in Brick-making? 25
4.2. Electricity Bills 27
5. Thermal Energy Model 28
5.1. Introduction 28
5.2. Structure of the Model 29
5.3. Best Practice Categories 32
5.4. Case Studies 34
5.4.1. Tunnel Kiln in the UK 34
5.4.2. Tunnel Kiln in South Africa 36
5.4.3. Vertical Shaft Brick Kiln (VSBK) in South Africa 38
6. Opportunities 40
6.1. Introduction 40
6.2. List of Best Practices 40
6.3. Business Cases 48
6.3.1. Replacing the current Clamp Kiln with a Fixed Kiln 49
6.3.2. Addition of Waste Products 55
6.3.3. Controlled and Efficient Combustion of Fuel 59
6.3.4. Use of Recent Model Mobile Plant and Movement Optimisation 63
6.3.5. Increasing Perforation Size of Extruded Bricks 67
6.3.6. Reduction of Thermal Mass of Kiln Car Decks Using Lightweight
Refractory or Fibre 72
6.3.7. Waste Heat Recovery 75
6.3.8. Variable Speed/Frequency Drives 79
6.3.9. Energy Management 81
6.3.10. Air Compressors 83
6.4. Energy Management Opportunities (and Reference to Existing Guides) 85
6.4.1. Relevance of ISO50 001 87
6.5. Industrial Symbiosis 91
6.6. Training 92
6.6.1. Green Skills Development Initiatives of the NCPC-SA 92
7. Next Steps 102
8. Appendices 103
8.1. Workshops 103
8.1.1. Pretoria Workshop 103
8.1.2. Cape Town Workshop 106
8.2. Common Energy Calculations 108
8.2.1. Specific Energy Consumption 108
8.2.2. Typical Energy Figures for Common South African Kilns 108
8.2.3. Useful Conversion Factors 109
8.3. Description of Kiln Technologies 109
8.3.1. Continuous Kilns 109
8.3.2. Intermittent Kilns 114
9. References 115
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 20166 7
The brick sector is a key player in the South African
industrial sector. The 100 or so industrial brick
companies in operation today produce some 3.5
billion bricks annually. While most of this production
takes place in clamp kilns, there are a number of
fixed kilns used, including tunnel kilns, Vertical
Shaft Brick Kilns, Hoffman kilns and others. These
guidelines set out the opportunities for the brick
sector to reduce its energy intensity, i.e. the energy
required per output of product (MJ/kg).
There are three types of benchmarks presented:
(1) Site specific; (2) Sector; and (3) International
Comparison. Setting targets to improve one’s own
performance is a great first step as it helps to focus
internal thinking on energy efficiency and has the
potential to make a huge impact on the reduction
of energy use. Obtaining sector-wide data on
production levels and total energy use helps the
entire sector to understand how it is performing
versus its peers, but also helps individual companies
to understand if they are performing in line with
their peers. We have seen - for instance in the UK -
how such information has been hugely beneficial to
the sector. The international comparison of energy
intensity of the South African brick sector shows
that South Africa generally performs in line with
other countries. For clamps, the international range
of energy required for drying and firing is 1.9MJ/
kg to 7.2MJ/kg, with the South African range
being 2.2MJ/kg to 5.2MJ/kg. Tunnel kiln energy
performance in South Africa is around 2.4MJ/kg,
slightly above the international range of 1.8MJ/kg
to 2.1MJ/kg.
Given that thermal energy accounts for more than
80% of energy use (though a lower % of total
energy costs, given the high cost of electricity), a
key finding of the project is the need for a deeper
understanding of thermal energy use among
both brick companies and the energy auditor
community. Many of the sector energy efficiency
audits undertaken to date have focused largely
on electricity best practices. A thermal model has
therefore been developed to help brick companies
better understand where the heat energy is flowing
in their plants, with the aim of restricting these
losses. It also points to specific measures that
can be adopted to reduce losses. Additionally, the
NCPC has recently run training workshops around
thermal energy reduction opportunities for brick
managers.
The guidelines then point to some 75 best practice
opportunities grouped into 10 areas. These
include “Improving combustion efficiency” and
“Reducing heat loss through kiln structure”. Each
best practice includes the cost of deployment, the
savings expected and the simple paybacks likely to
be achieved. The guidelines then take 10 of these
best practices and provide very detailed business
cases for them, which we hope will help brick
manufacturers feel confident about implementing
the measures.
The guidelines present the Energy Management
Systems (EnMS) approach to energy efficiency,
including discussion on ISO50001 and the training
available to industry.
The EECB will be looking to demonstrate a number
of these best practices in 2016 for completion by
the end of 2016, with dissemination of the findings
in 2017, including case studies, events and other
support.
Executive Summary
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 20168 9
1.1 Project ObjectivesThe project aims to develop guidelines that will
help the South African brick sector to reduce its
energy costs and become more energy efficient.
Specifically, the guidelines would provide a deeper
understanding of the international benchmarks of
energy use, and assist fixed kiln sites to visualise
their thermal energy flow and understand the
best practices and business cases that could be
relevant to them.
In order to achieve this, the project undertook
a series of activities, analysis and sector
engagements, including:
• Literature review of international best practices
to assess the energy intensity of a range
of brick kiln types (including clamps and
fixed kilns) across key markets (China, India,
Bangladesh and UK).
• Analysis of a number of audits at brick sites
completed by the Private Sector Energy
Efficiency Programme (PSEE) and the National
Clean Production Centre (NCPC).
• Development of a thermal energy model
to identify where losses are for fixed kiln
manufacturers.
• Identification of the best practice opportunities
for the industry across both thermal and
electrical energy use that include indications
of cost to deploy, as well as the savings
achievable.
• A number of detailed business cases that show
how best practice can be deployed, the
maturity of the technology, more detailed cost
analysis, and the barriers and risks involved
with deployment.
• Presentation of an Energy Management
(EnMS) approach and ISO 50 001, including
training undertaken by NCPC.
• Workshops to source industry perspectives,
prioritise best practices and better understand
the challenges faced.
1.1.1 Energy Efficient Clay Bricks (EECB)
Programme
The Swisscontact-implemented EECB Project,
funded by the Swiss Agency for Development and
Cooperation, has been working actively with the
clay brick sector across three dimensions:
• Supply: Encouraging energy efficiency among
brick makers;
• Demand: Ensuring that specifiers and
developers are fully cognisant of the
environmental credentials of brick as a building
product;
• Enabling Environment: Influencing
government and other key stakeholders to
provide opportune policies and conditions in
which energy efficiency is supported, as well
as collaborating with financial institutions
seeking opportunities for the funding of energy
efficiency measures.
1.1.2 The Importance and Challenges of
Energy Efficiency
With rising energy costs for both electricity and
fuels, and given that in the brick sector, energy can
account for between 40% and 60% of production
costs, energy efficiency represents a significant
opportunity for cost reduction.
However, there are many barriers to deploying best
practice energy efficiency measures, the following
in particular:
1. Knowledge of the opportunities: Having a
clear understanding of the various best
1. Introduction
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201610 11
01 02 03 04 05Energy Audits Baseline
BenchmarkingOpportunities
Business CaseEnergy Efficiency Implementation
Energy Efficiency Demonstration
Brick makers adoptenery efficiency measures
Brick makers demonstrateenery efficiency measures
AREAS OFINTERVENTION WITHIN MARKET
SYSTEMS
SUPPLY:Clay Brick Makers
Adopt Energy Efficient Practices
ENABLINGENVIRONMENT:
Conductive Policies and Busienss Environment for an Energy Efficient
Clay Brick Sector
DEMAND:Building Sector
Awareness of EnergyEfficiency Measures in
Clay Brick Sector
Improving access to knowledge, skills, technologies and delivery mechanisms for clay brick producers
Facilitating access to finance and improving policy dialogue within stakeholder platforms
Target Building sector actors motivated to use
energy efficiently produced clay bricks
Brick makers adopt energy efficiency measures
Brick makers demonstrate energy efficiency measures
01
0203
Figure 1: Approach of the EECB Programme
Figure 2: Project’s structure and approach
This project looks to address the supply side to
ensure supply understands how it is performing
versus international companies, as well as
providing specific energy efficiency measures
that can be implemented.
Importance of EECB
EECB Project Reminder
practice measures that can be deployed, both
technically and in terms of investment return;
there are often complex considerations for
process specific measures.
2. Energy Manager to focus on assessing
these: Ensuring that companies have the
required personnel for whom energy efficiency
is a key part of their role.
3. Finance to deploy them: Financial resources
to meet upfront costs; requires access to
capital to be able pay for the best practice
measure and convincing the Finance Director
that this has material impact on the business.
4. Understanding of how to deploy: Knowing
exactly how to deploy the solution and having
confidence in the suppliers and consultants
who will ultimately design and deploy the
solution.
1.2 Key Stakeholders
Critical to the success of the development of the guide is engagement with a number of key stakeholders, many of them already engaged with EECB at various levels within the EECB stakeholder grouping.
They will have different levels of input into the
project, and include:
• Swisscontact: Critical - as the funder, through
the EECB Project, for the development of
the guidelines, and given the relationship to
date with the trade association and others,
Swisscontact involvement is crucial.
• Clay Brick Association: Critical - Representing
around 100 brick makers as members of the
association.
• Brick Manufacturers: Critical - provide sites
for audit, provide access to data and provide
ideas.
• Equipment Suppliers: Important - provides
ideas, as well as being integral to the work
programme described above.
• Government: Helpful - it is always useful to
have a government department represented to
ensure they are also supportive of the project
and its conclusions.
• Private Sector Energy Efficiency Programme
(PSEE): Important - works in partnership with
business to provide advice and audits on
energy efficiencies to small, medium and large
companies.
• National Cleaner Production Centre
(NCPC): Important - promotes the
implementation of resource efficiency and
cleaner production methodologies for industry.
It also offers training on Energy Management
(EnMS) approaches and on ISO50001.
• Universities and Research Institutes:
Optional - since this is not innovation-focussed,
this group is helpful but not critical.
1.3 Activities Currently Undertaken by Other Organisations
There are activities taking place that are relevant
to mention here, as they help to inform work on
energy efficiency. These include:
• Brick Sector Marketing: The CBA, as part of
its ongoing remit, conducts marketing on behalf of
the industry to ensure the sector is well positioned
with its customers and demonstrates benefits
linked to:
o Quality;
o Price versus competing products (such as
glass, stone and wood);
o Environmental credentials; and
o Aesthetics.
• Site Audits: The PSEE and the NCPC
completed a number of brick sector audits with
recommendations to the host companies on
energy efficiency opportunities.
• Training: The NCPC conducted training to
the brick sector on energy efficiency
opportunities and EnMS approaches (see
Section 6.6).
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201612 13
2. The South African Clay Brick Sector
2.1 Typical Clay Brick Production Methodology and Product Variations across the Sector
2.1.1 Clay Brick Basics
Generally, the raw material clay is mined or won
from a clay quarry, pit or mine. In South Africa, a
wide range of raw materials is used, including
various forms of kaolin, shale and clays of different
types. After quarrying, the material is often
stockpiled and allowed to weather for a certain
period before being ground to a fine consistency,
mostly by means of a crushing or grinding facility
(generally <2.5mm). In some countries, the
grinding step can be very rudimentary, but in South
Africa, grinding is generally highly mechanised.
The prepared material is then mixed with water
to a consistency that allows it to be shaped into
a brick. Many countries use mechanisation to
achieve this, but others still make use of basic
hand-mixing and shaping via a wooden mould box.
In South Africa, the mixing and shaping is generally
done via mechanisation, which can produce up
to 700,000 bricks a day from a single plant.
After shaping, bricks must be dried before they
are fired so that they don’t crack during the firing
process. Drying can be mechanised or done by
simply making use of the sun and wind; this is still
commonplace in South Africa. The final step – firing
- is the most energy intensive as it involves heating
the bricks to temperatures of around 1000ºC in
order to vitrify them and give them their durability.
2.1.2 Simple Drying and Firing Technology
in South Africa
As mentioned above, it is commonplace in South
Africa that the drying step be carried out in the
open air. This is done for reasons of capital cost,
simplicity and the firing method most commonly
employed in South Africa, known as a clamp kiln.
Clamp kilns are repeating structures built from
unfired bricks surrounded by a thin casing of usually
unsaleable fired product. Due to their nature, it is
not possible to recover waste heat from clamp kilns
for use in the drying process (see picture alongside
of a clamp kiln). This generally results in clamp kiln
producers being reliant on the weather for drying
and consequently, their businesses can be severely
affected by prolonged adverse weather conditions.
Clamp kilns themselves can also be negatively
affected by inclement weather. They are essentially
uncontrolled firing structures that once constructed
and lit, are left at the mercy of the elements for firing
of the bricks inside the kiln to occur. Energy for firing
is commonly provided by pulverised coal known as
duff, which is mixed into the body of the product
during the milling and shaping process. At present,
it is estimated that between 60% and 70% of the
bricks made in South Africa are produced in clamp
kilns. Clamp kilns are known to be very inefficient
in their use of firing energy and they are also often
criticised for high levels of atmospheric pollution.
Due to increases in coal costs, labour costs and
pollution control legislation, there is mounting
pressure on clamp kiln producers to convert their
operations to different firing technologies. Indeed, it
is no longer possible for a new clamp kiln operation
De Giovanetti & Volsteedt (2013) suggested the
reasons for the delays include a conservative
mindset and an unwillingness to change, lack of
access to finance and environmental red tape.
Additionally, an often-overlooked factor is that
clamp kilns can create a reducing atmosphere
when firing, thus producing more aesthetically
appealing bricks. These bricks can be sold as a
semi-face brick for a significantly better margin
(see below for differentiation between plaster and
face bricks). This improved margin on a portion
of the bricks produced can be quite lucrative for
a clamp kiln manufacturer, and therefore clamp
producers would prefer not to risk losing it.
to obtain an operating licence (Mienie, 2014).
Cumulatively, these factors have led to concerted
efforts towards finding suitable alternative firing
Figure3: South African Clamp kiln
To date, notwithstanding the advantages offered,
the alternative firing technology that has garnered
the most press in South Africa cannot recreate a
reducing atmosphere (in its current guise). With a
reasonable capital investment into the construction
of a Vertical Shaft Brick Kiln (VSBK) plant (as
opposed to almost no capital investment in the
construction of a clamp kiln), a brick producer can
drop firing energy usage to some 30% – 50% of
that used in a clamp kiln and greatly reduce its
carbon footprint (De Giovanetti & Volsteedt, 2013).
With energy costs making up to 40% of the cost
of producing a brick, the potential for significant
cost savings is clear. Additionally, clamp kilns
methods to clamp kilns in South Africa, but clamp
producers collectively are reluctant to embrace
change.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201614 15
typically produce as much as 15% – 25% waste,
due to their uncontrolled nature, whereas the pilot
VSBK plant in South Africa is running at 2% waste
(De Giovanetti & Volsteedt, 2013). The industry
game-changing potential of this technology (over
clamp kilns) is clear, but it is not the only option.
Hoffman kilns or derivatives thereof enjoy
continued popularity in some parts of the world.
In South Africa, a common term for a Hoffman
derivative is the transverse arch kiln, of which
there are a few examples in operation. Zig-Zag
kilns also operate effectively in many parts of
the world and there is currently much interest
in bringing this technology to South Africa. As
per VSBKs, Hoffman and Zig-Zag technologies
promise efficiency gains and pollution and waste
reduction over clamp kilns, and may also be able
to recreate a similar reducing atmosphere to
clamp kilns. Nevertheless, most of these simple
technologies - despite their advantages over clamp
kilns - suffer from similar maladies, as listed below.
• VSBK, Hoffman and Zig-Zag technologies
are specifically firing technologies. Hoffman
and Zig-Zag can handle some limited drying,
whereas VSBK has no capacity for drying.
Therefore, many producers relying on these
technologies will still be influenced by the
weather or will require other energy sources to
supply heat to separately constructed dryers.
• These simple technologies often make use of
manual handling of each brick in the unfired
state. This significantly reduces the potential to
produce a top quality product and potentially
adds to the amount of waste produced.
• Simple technologies are generally labour
intensive and less suited to automation, and
therefore more prone to process issues.
Additionally, similar reasons can limit the
scalability of the technology. Particularly with
VSBKs, the ability of these technologies to
replace high output clamp yards remains
unproven.
• With VSBKs, the firing atmosphere is
currently exclusively an oxidising environment.
This has implications with regards to the
potential for increased margins on the
production of facing bricks. Also, due to the
weight-bearing nature of the set product,
VSBKs have limitations with regards to the
percentage of voids in the bricks produced.
2.1.3 Brick Types
When a house is constructed using face brick as
the outer wall, the current norm in most areas of
South Africa is that the outer walls should be of
cavity wall construction (Grobbelaar, 2006). This
method of construction prevails due to its damp
sealing characteristics and energy efficiency.
Generally, the outer face brick wall (outer ‘skin’)
encloses a cavity which is in turn enclosed from
the other side by another brick wall. The inner ‘skin’
is built from plaster brick which is usually plastered
to create the smooth, visible surface which most
people paint. As plaster bricks are no longer visible
after plastering, they are generally not of as high
or uniform quality as the face brick on the outside.
As a general rule, that which can be seen – the
face brick – attracts far more attention in the
design and specification stage than that which
cannot be seen – the plaster brick. The architect,
developer or eventual occupant of the building
is generally interested in the aesthetic appeal of
the structure and hence pays particular attention
to the choice of face brick. The plaster brick on
the other hand, is generally chosen on the basis
of price, quality and ease of use. This choice
is often made by the builder or contractor –
a different scenario to that of the face brick.
Naturally, both face brick and plaster brick are
affected by a few similar issues. These include
the service of the sales organisation, availability
of the product and the price. However, the
commodity nature of a plaster brick is inescapable
and they are far more price-sensitive than face
bricks. This adds to the challenges faced by
plaster brick manufacturers in South Africa.
With reference to SANS 227:2007, the common
nomenclature and tolerances for clay brick units
Table 1: Common nomenclature and tolerances for clay masonry units (SANS 227:2007)
TYPES A N S
CodeDESCRIPTION
Tolerances (mm) over average
32 units (individual units as
applicable)
Length Width Height
FACE BRICK
FBX
Face Brick Extra
Clay bricks that are selected or produced
for their durability and high degree of
uniformity of size, shape and colour.
± 2.5
(± 5)
± 1.5
(± 3)
± 1.5
(± 3)
FBS
Face Brick Standard
Clay bricks that are selected or produced
for their durability and uniformity of size
and shape.
± 3.5
(± 7)
± 2
(± 4)
± 2
(± 4)
FBA
Face Brick Aesthetic
Clay bricks that are selected or produced
for their durability and aesthetic effect
deriving from non-uniformity of size, shape
or colour.
- - -
NON-FACE
(PLASTER)
BRICK
NFP
Non Facing Plastered
Clay bricks suitable for general building
work that is to be plastered.
± 3.5 ± 2 ± 2
NFX
Non Facing Extra
Clay bricks suitable for use, plastered or
un-plastered, for general building work
below damp-proof course or under damp
conditions or below ground level where
durability rather than aesthetics is the
criterion for selection.
± 3.5 ± 2 ± 2
made in South Africa and relevant to this plan are
summarised in Table 2.1. The most common size
of plaster and face brick made in South Africa is
the “Imperial Brick” with dimensions of 222mm
long x 106mm wide x 73mm high. Imperial-sized
brick products may be solid or may have holes
through it (coring) for weight reduction, but either
way, can be regarded as a commodity product - “a
product that is the same as other products of the
same type from other producers or manufacturers”
(Cambridge University Press, 2014)).
2.2 Brick Sector Production Levels and the Construction Industry
It is estimated that there are about 100 industrial
brick producers in South Africa, representing a
total production capacity of approximately 3.5
billion bricks per year (CBA, 2014).
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201616 17
Clamps TVATunnels Other (incl. zig-zag)
VSBK
22
17
6070
60
50
40
30
20
10
0
4
Construction contributes significantly to South Africa’s economy, but has been in decline over the
past seven years. The growth witnessed in the run up to the 2010 World Cup – between 2004 and
2007 – has not been seen since. 2008 saw the start of the decline with investment dropping by
almost 12% in 2010. Growth has been relatively flat since then. The decline has led to intense margin
pressure and manufacturers operate at extremely slim profit margin, often between just 2% and 3%.
The total income for the construction industry in 2014 was R395 026 million. The largest contributor related to
Civil Engineering Structures (37%), followed by Buildings (23%).
The vast majority (more than two-thirds) of South African brickworks employ clamp kiln firing technology,
followed by tunnel kilns (14% of brickworks). Transverse Arch (TVA) Kilns are a derivative of the Hoffman
Kiln design. Only a small percentage of the brickworks companies in South Africa have started to employ
the Vertical Shaft Brick Kiln (VSBK) technology (2%).
The energy intensity of the firing process varies considerably depending on the kiln type. A detailed
comparison of specific energy consumption (SEC) in South Africa and abroad by kiln types is given in
Chapter 3.
While 70% are clamps,
tunnel kilns are 20%
Other technologies
are increasingly being
considered by many sites
Discussions with brick makers have indicated that most have substantially reduced production and are now operating
at well below capacity, given the weak demand.
Construction of civil engineering structuresR145 383m (37%)
All other construction
activitiesR88 382m
(22%)
Other building installation R31 560m
(8%)
Other building completion R38 094m
(10%)
Construction of buildings R91 607m (23%)
22%
8%
10%
37%
23%
73%
14%
6% 2%
4% 1%
Clamp Kiln
Hoffman Kiln
Tunnel Kiln
Bulls Trench Kiln
Traverse Arch Kiln
Vertical Shaft Brick Kiln
Figure 3: Income from the construction industry
Figure 4.1: Breakdown of % of sites by kiln technology
Figure 4.2: Breakdown of % of sites by kiln technology
2.3 Breakdown of Kiln Technologies and Number of Sites
A breakdown of the split of South African brickworks in terms of kiln technologies employed is shown in
the following charts.
Brick sites by Kiln Type
Brick sites by Kiln Type
Of the 85 or so industrial sites, clamp
kilns dominate
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201618 19
3.1 IntroductionIt is estimated that there are 300,000 brick kilns
throughout the world manufacturing 1,500 billion
bricks per year. Coal is by a large margin the main
fuel used for brick-making; it is estimated that
the brick industry consumes 50 million tonnes
of coal per year out of 7,000 million tonnes
mined each year. In term of emissions, the brick
industry is responsible for about 100 million
tonnes of CO2 per yearout of 8,000 million tonnes
released each year from fossil fuels. Along with
other industries, brick makers will benefit from
reducing their CO2 emissions by reducing their
fuel costs per brick and their liability for any carbon
taxes now or in the future. This chapter looks at
the performance of various types of kilns from
around the world, highlighting the differences in
efficiency and the potential for energy reduction.
Benchmarks can be applied at multiple levels,
including:
1. Site specific benchmark;
2. National sector benchmarks;
3. International sector benchmarks.
1. Site Specific Benchmark
The site specific benchmark is used to drive
2. The Sector Benchmark
Sector benchmarks are used to measure how a
company is performing against its competitors and
to identify the reasons for the difference. It helps
the company to understand its relative competitive
position.
Sector benchmarking requires cooperation
between manufacturers. There is a common
interest for brick manufacturers to maintain a
competitive position versus brick substitutes (e.g.
cement, glass, stone, wood, etc.).
Figure 6 illustrates a hypothetical market with a
gaussian shape. It shows the importance of sector
benchmarks in order for factories to know their
position in the market and identify why they are
continuous improvement in a business through
a quality management process and to measure
the benefits derived from the process decisions.
In the example below, the energy consumption of
a UK brick factory is plotted versus time. On the
left-hand side of the graph, the red mean shows
the average energy consumption before any
measures were taken. It shows the high variability
of energy consumption throughout the year prior
to the adoption of any performance targets. The
company instigated a performance monitoring
programme using a benchmark – the green
line- and rapidly saw its energy consumption
naturally stabilising below their previous mean,
thus saving energy by simply carefully monitoring
their energy consumption and responding
immediately to any deviation above the benchmark.
All the savings were achieved simply by
improving current practices and no investment
was required. The right-hand side of the graph
shows the additional savings that the company
calculated it could achieved through investment
in new energy saving opportunities. The stable
operating performance enabled the business
case to be more accurately calculated and a more
compelling case made to the board of directors.
3. Benchmarks
120
100
80
Ene
rgy
Use
Time
mean
benchmark
Current performance Current performanceInnovative deployment
innovation ornew technology
60
40
20
0
No
of S
ites
Firing & drying energy
Best in sector
Mean Our site Market substitutebenchmarks
WHY?
requires co-operation between manufacturers
250,000
200,000
50,000
150,000
100,000
Ann
ual C
onsu
mpt
ion
Mw
h
Annual Production, Tonnes
50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,0000
0
R =0.7419
R = 0.8236
electricity
gas
Figu
re 5
: Exa
mpl
e of
redu
ctio
n of
ene
rgy
cons
umpt
ion
thro
ugh
pers
onal
ben
chm
arki
ng
Figu
re 6
: Fic
tive
exam
ple
of s
ecto
r ben
chm
arki
ngFi
gure
7: U
K b
rick
sect
or b
ench
mar
king
better or worse than other sites.
Figure 7 depicts a real example of sector
benchmarking undertaken for the UK brick market.
Each factory’s electrical and thermal energy
consumption has been plotted in the graph and
linear regressions show the market averages. A
site which is below the regression line is more
energy-efficient than the market average, while a
site which is above the line is less energy-efficient.
This type of exercise is valuable for every company
to compare itself against the rest of the market.
The R2 values on the regression lines show the
degree of correlation between the regression
and the data. A value less than 0.5 means there
is little correlation and above 0.8 there is a strong
correlation.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201620 21
3. The International Sector Benchmark
Finally, the national sector’s performance can be
compared to international markets, to evaluate
how they are performing as a whole against other
countries. This is a similar approach as the national
sector benchmark, but comparing markets rather
than individual sites. This section examines the
energy consumption of kilns used throughout
the world. It draws on published data and also on
detailed information from the UK sector held by the
Carbon Trust.
Clay bricks require heat to dry them and to fire
them. Drying requires low temperature heat (below
150oC) to evaporate the water in the clay, whereas
firing requires high temperatures of 1000oC or
above. This heat is usually provided by a fossil
fuel such as coal, oil or natural gas, however
the presence of organic matter in clay can also
contribute significantly to the heat requirement for
firing. For example the lower Oxford clays in the
UK used to make fletton bricks contain around 2%
- 4% combustible carbon, which is almost sufficient
to fire the bricks without the addition of more fuel.
Most data included in this section excludes the
natural organic carbon in the clay and accounts
only for purchased fuels.
Energy consumption in this report is reported as
a specific energy consumption (SEC) representing
the amount of energy required to fire a unit mass of
brick. Where possible we have used MJ/kg.
• The United Kingdom
Within the UK, the majority of bricks are produced
using modern tunnel kilns using natural gas for
the fuel. The UK - like the rest of the EU and
North America - tends to have large mechanised
factories using much less labour than many brick
factories in other countries, such as India, China
and South Africa. A reliable electricity supply is
essential for these factories as brick making,
drying and firing processes all rely on power to
operate machinery and air movement equipment.
Electricity consumption is around 8% of the total
energy consumption for brick making in the UK.
A survey of 73 brick kilns in the UK sector found
a wide range of thermal efficiencies for the firing
and drying processes as shown in the table below.
• China
China is the largest brick producer in the world, manufacturing 750 billion bricks per year, with the majority
of these being produced in continuous chamber kilns (Clean Air Task Force, 2010). China does deploy
other technology as well, including clamp, intermittent, tunnel and Vertical Shaft Brick Kilns (VSBK).
• India
India is the second largest brick producer in the world, manufacturing 140 billion bricks per year, with 70%
of production from Bulls Trench Kilns (Clean Air Task Force, 2010). India also deploys other technology
as well, including clamp, intermittent, tunnel and Vertical Bhaft brick Kilns (VSBK).
Country Technology1SEC
MJ/kg
2SEC
MJ/kg
UK Intermittent kiln; Firing only 3.7
UKBest Practice Fuel UK Drying & Firing; Tunnel kiln;
Moisture content 15%1.3
UKBest Practice Soft Mud Drying & Firing; Tunnel kiln;
Moisture content 28%1.8
UK Drying & Firing; Mean of 73 kilns 2.3
EU Drying & Firing; Tunnel kilns 2.3
Sources:1Carbon Trust, 2012; 2IEA, 2007
Table 2: Benchmarking of specific energy consumption (SEC) for kilns in the UK
Country Technology1SEC
MJ/kg
2SEC
MJ/kg
China Intermittent kiln 2.47 2.5
China Annular kiln with natural drying 1.16-1.46 1.2-1.5
China Annular kiln with artificial drying 1.39-1.56
China Tunnel kiln 1.29-1.52 1.3-1.5
China VSBK none found
All energy consumption includes the energy requirement for drying unless stated otherwise.
Sources: 1Swiss Agency for Development and Cooperation; 2UNIDO, 2010
Country Technology1SEC
MJ/kg
2SEC
MJ/kg
India Clamp 1.5-7
India Intermittent chamber kiln 3-11 2.9
India Bulls trench Kiln 1.8-4.2 1.22
India Hoffman Kiln 1.5-4.3
India Tunnel kiln 1.5-2.0 1.49*
India Zig-zag kiln 1.12
India VSBK 0.95
All energy consumption includes the energy requirement for drying unless stated otherwise.
*Includes heat required for drying
Sources: 1Swiss Agency for Development and Cooperation; 2Sakkti Sustainable Energy Foundation, 2012
Table 3: Benchmarking of specific energy consumption (SEC) for kilns in China
Table 4: Benchmarking of specific energy consumption (SEC) for kilns in India
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201622 23
• Bangladesh
Brick production in Bangladesh is around 50 billion bricks per year (Clean Air Task Force, 2010). Like
India, the majority of kilns are Bulls Trench Kilns but with other kiln types that are regarded as less
polluting becoming more popular, such as the Zig-zag kilns and VSBK.
Table 6 shows that the best Hoffman and VSBK
kilns can beas efficient as modern tunnel kilns.
This suggests that with the right technology and
management practices, these technologies can be
operated at global best practice levels of energy
efficiency. Clamp and intermittent kilns are clearly
a lot less efficient.
Using this table and the heat balances, we can
construct some firing energy benchmarks for
manufacturers to compare themselves against,
based on the technology they are deploying,
and thus determine the level of potential savings
they could realise by deploying some of the best
practices recommended within this report.
From energy surveys carried out for a sample of
brickworks in the country, the range of SEC for
South African kilns was compared to international
figures. It is evident that the energy intensity of
clamp kilns varies considerably in South Africa but
is comparable to international figures. The tunnel
kilns assessed have higher than international
energy intensities, whilst TVA kilns are in the
international range of SEC.
Non-continuous kilns: SEC data from South
African Clamp kilns (in green) are well within the
range of international clamp kilns, with the most
energy efficient ones approaching the international
benchmark. However, the range is very large,
showing margin for significant energy efficiency
improvements. No intermittent chamber kilns were
reported in South Africa.
Continuous kilns: No data is provided for Zig-zag
kilns as data for only one kiln was found in literature,
which is insufficient to draw relevant conclusions.
There are currently two VSBKs in South Africa,
one of them as efficient as the best VSKBs
abroad and the other well above. It is important to
note that VSBKs’ SEC represented in the graph
are for firing only; hence, it cannot be compared
with other technologies whose SEC includes the
drying process. Other South African continuous
kilns (tunnel and TVA kilns) seem to be in the
lower end or above their international counterparts,
thus indicating significant opportunities for energy
savings.
Country Technology1SEC
MJ/kg
2SEC
MJ/kg
Bangladesh Intermittent Kiln 2-4.5
Bangladesh Bulls Trench Kiln 1.3-1.9 1.2
Bangladesh Hoffman Kiln 0.9
Bangladesh VSBK 1.2
All energy consumption include the energy requirement for drying unless stated otherwise.
Sources: 1ESMAP, 2011;2UNIDO, 2010
Table 6: Summary of specific energy consumption (SEC) benchmarking by technology
Technology Country SEC MJ/kg
Clamp India 1.5-7
Intermittent Chamber Kiln
UK 3.7
China 2.5
India 3-11
Bangladesh 2-4.5
Bulls Trench KilnIndia 1.8-4.2
Bangladesh 1.2-1.9
Hoffman Kiln (including annular kiln)
China1.2-1.5
(1.4-1.6)
India 1.5-4.3
Bangladesh 0.9
VSBKIndia 0.95
Bangladesh 1.2
Tunnel Kiln
UK best practice (15% moisture)
UK best practice (28% moisture)
UK mean
EU mean
(1.3) 0.7
(1.8) 0.8
(2.3) 1.2
(2.3)
China 1.3-1.5
India 1.5-2.0
Zig Zig Kiln India 1.1
Data in brackets include heat for drying. All other data excludes heat for drying.
Clamp IntermittentChamber Kiln
Bulls Trench,Hoffman, TVA
Kiln
Zig Zag Kiln VSBK
Firing only
Tunnel Kiln
South Africa
IndiaBangladeshChinaIndia
IndiaBangladesh
UK EuropeIndiaChina
Dry
ing
& F
irin
g M
J/kg
0.0
2.0
4.0
6.0
8.0
10.0
12.0
?
UKIndiaChinaBangladesh
Figure 8: Summary of international (purple) and South African (green) ranges of specific energy consumption (SEC) for the drying and firing processes by technology
Fuel
Con
sum
ptio
n by
Tec
hnol
ogy
Table 5: Benchmarking of specific energy consumption (SEC) for kilns in Bangladesh
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201624 25
Crushers & Grinders
Extruder
Mixers
Conveyors
Dryer & Kiln (fans)
Pumps & Compressors
Others (eg. lightings, office, etc.)
23%
19%36%
8%4%
7%3%
3.1.1. Continuous Kiln Benchmarks
The theoretical minimum was computed, considering the following assumptions:
• 2% moisture content of bricks entering kiln • Exhaust is 200oC
• Bricks leaving the kiln cooling zone at 200oC • Structural loss of 0.2 MJ/kg fired brick
• 100% excess air
Note: other values for a theoretical minimum could be obtained using different assumptions.
The table shows that the best practice kiln is close to the theoretical minimum calculated. These two
values should be used by continuous kiln operators as targets for energy efficiency improvements.
3.1.2. Advantages and Disadvantages of the Main Brick Kiln Types
In this section, the various kiln types were assessed as Low, Medium and High, based on nine criteria.
Negative aspects of the kilns are flagged in red, while positive aspects are marked in bold. Note that it is
a non-exhaustive list and other criteria may come in the balance when comparing or choosing a new kiln
to fire the bricks without the addition of more fuel.
It is clear from the table below that each type of kiln has its own advantages and disadvantages. Tunnel kilns
come out as the option with the highest number of advantages, especially around control opportunities
and quality, but it is also the most expensive one. VSBKs have very few weaknesses, offering good
overall performance with reasonable capital cost, with its main disadvantage being low flexibilty. Hoffman
and Zig-zag kilns are interesting options, although less attractive than VSBKs and Tunnel kilns based
on the table above. Intermittent chamber kilns have many advantages but are expensive both in term of
capital cost and fuel consumption. Finally, both Clamp and Bulls Trench Kilns have a fairly high number of
disadvantages, but remain the cheapest options.
Continuous KilnsBest Practice
MJ/kg
Theoretical Minimum
MJ/kg
Firing only 0.7 0.6
Table 7: Best practice and theoretical minimum SEC for continuous kilns
ClampInter-mittent Chamber
Bulls Trench
Hoffman Zig Zag VSBK Tunnel
Capital cost Low High Low Med Med Med High
Labour cost High Med High High High Med Low
Fuel cost High High Med Low Low Low Low
Pollution High Low High Med Med Med Low
Operator safety Low High Low Med Med Med High
Level of control Low High Low Med Med Med High
Quality variation High Low High High High Med Low
Flexibility Low High Low Low Low Low High
Electricity required No Yes No No No No Yes
Table 8: Comparison between kiln types
4.1. Where is Energy Used in Brick-making?
A number of energy audits have been carried out
in South Africa showing a breakdown of the total
energy use in brick factories. Note that the analysis
below is only based on a small sample of the South
African brick plants and does not represent the
market’s averages.
Drying and firing are the most energy-intensive
steps in a brickworks by a large margin. These
are also the only processes using thermal energy
rather than electrical energy. Thermal energy use is
analysed in the next section using a tool developed
for this purpose. This section focuses on the use of
electrical energy only.
The following two tables provide examples of the
breakdown of electrical energy use for three sites
using continuous kilns and three site using clamp
kilns in South Africa.
4. Performance of the Sector
Sites operating continuous kilnsSite 1(Tunnel kiln)
Site 2(VSBK)
Site 3(Tunnel kiln)
Mot
ors
Crushers & Grinders 38% 28% 7%
Extruder 32% 13% 11%
Mixers 9% 9% 7%
Conveyors Incl. above 4% 4%
Dryer & Kiln (mainly fans) 11% 39% 58%
Pumps & Compressors 2% 5% 2%
Others (e.g. lightings, office, etc.) 8% 2% 11%
Table9: Breakdown of electrical energy use in three South African brick factories using continuous kilns
Figure9: Average breakdown of electrical energy use for three South African brick factories using continuous kilns
Breakdown of electrical energy use in three sites operating continuous kilns
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201626 27
Crushers & Grinders
Extruder
Mixers
Conveyors
Dryer & Kiln (fans)
Pumps & Compressors
Others (eg. lightings, office, etc.)22% 26%
24%7%
7%
10%
3%
Sites operating clamp kilnsSite 1(Clamp &fixed kiln)
Site 2(Clamp)
Site 3(Clamp)
Mot
ors
Crushers & Grinders 16% 7% 50%
Extruder 23% 38%40%
Mixers 19% 39%
Conveyors 15% 7% Incl. above
Fans 10% 0% 0%
Pumps & Compressors 10% 4% Incl. above
Others (e.g. lightings, office, etc.) 7% 5% 10%
Table 10: Breakdown of electrical energy use in three South African brick factories using clamp kilns
Figure 10: Average breakdown of electrical energy use for three South African brick factories using clamp kilns
Breakdown of electrical energy use in three sites operating clamp kilns (one site also operating a fixed kiln)
In clamp kiln sites, motors, in particular extruders,
crushers and mixers, dominate the electricity
consumption. All motors represent over 80% of the
electrical energy use in clamp kiln sites. There is
therefore a significant incentive to improve motors’
efficiency through, for example, motor efficiency
retrofits on less efficient motors, replacing oversized
motors or replacing existing standard solid
V-drive belts with other types of belts. However,
electricity is also used in ancillary processes such
as compressors, lighting, small power and offices.
Compressor control, leak surveys and energy
efficient lighting are all well-known and worthwhile
initiatives to reduce ancillary consumption.
In sites operating continuous kilns, the picture
is different; fans used for the drying and firing
processes make a major part of the total electricity
consumption. As a result, fan system optimisation
(e.g. type of fans, de-commission of some fans,
use of variable speed drive, etc.) is a very attractive
energy saving opportunity for continuous kilns. The
electrical energy saving from fans is closely related
to the efficiency of heating, hence the optimisation
of thermal energy use can also result in electricity
savings.
Similar to clamp kiln sites, extruders, crushers and
mixers are responsible for most the rest of the
electricity consumption.
4.2. Electricity BillsA significant reduction in energy bills can be achieved through better energy management. Audits have
revealed that in several instances, network demand charges are responsible for almost half of electrical
energy costs.
A notified maximum demand is set for each
plant and if this demand is exceeded, penalties
are incurred. Such penalties resulting from
uncontrolled maximum demand can account for a
high percentage of the total monthly electricity bill.
The Notified Access Charge (NAC) is a fixed
kVA value which should never be exceeded. An
uncontrolled or unplanned kVA event will result in
a penalty for the next 12 months ahead.
The maximum or peak demand in kVA is billed
according to the half hour of the month in which
the maximum demand was reached. Thus the
half hour in the month in which the average
consumption was the highest, is the peak demand
for that specific month. The peak demand most
probably occurs when large energy consumers are
starting up simultaneously. Therefore, there is an
opportunity for savings on the electricity bill, should
maximum demand control be implemented. Real
time measurement and monitoring with a built in
automated maximum demand control feature give
the ability to prevent any unplanned energy spikes.
Significant savings can also be achieved by moving
outside of peak periods and minimising energy
consumption during high season. The following
table shows three examples of brick factories
with an average of 20% energy use during peak
periods, resulting in a large increase in total
electricity costs.
Electricity bill Site 1 Site 2
KWh energy charge 57% 53%
Network demand charge 38% 47%
Service charge 5% 0.4%
Table 11: Breakdown of electricity bills for two South African brick factories
KWh energy charge Site 1 Site 2 Site 3
Standard periods 58% 60% 44%
Off-peak periods 26% 17% 39%
Peak periods 16% 23% 17%
Table 12: Breakdown of KWh energy charge for three South African brick factories
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201628 29
5.1. IntroductionThermal energy is an area that is often neglected when considering reducing energy consumption.
Energy audits are typically focussed on electrical energy, as thermal energy losses are often harder to
identify and quantify. Nevertheless, heat used in the drying and firing processes accounts for a majority
(typically over 90%) of the total energy consumption in a brick factory.
5.2. Structure of the ModelThe model was built using Microsoft Excel and can run on every computer, although some older versions
of the software might prevent it from using embedded Macros. The file is structured in three main sheets:
1. The inputs interface;
2. The output sheet showing the energy balance of the system;
3. The best practice sheet generating relevant opportunities.
Structure of the model
1. Data of a specific plant are entered in the Input sheet
2. The model calculates the energy balance
3. A list of energy saving oppportunities automatically generated
A fourth sheet called “Saved Data” can be used to store data. This data can then be sent to the inputs
sheet, thus saving time and avoiding the need to type each data in the inputs sheet every time one wants
to visualise the outputs. For example, a plant manager might want to save plant data on year 1, year 2 and
year 3 for comparison purposes.
In response to this opportunity, the project
developed a thermal energy tool to enable brick
plant managers to:
1. Establish a full breakdown of thermal energy flows in their manufacturing process;
2. Identify main areas of thermal energy losses;
3. Identify relevant opportunities to reduce energy consumption;
4. Quantify these opportunities and benchmark their plant with best practice brick plants internationally.
The free tool is available to anyone and can be
found on CBA’s website:
http://www.claybrick.org.za/energy-efficiency-
guidelines/thermal-model.
The tool was developed for all types of
continuous or fixed kilns, e.g. tunnel kilns,
VSBKs, Hoffman kilns, Zig-zag kilns and BTKs.
It cannot be used for clamp kilns, which are
batch processes. Whilst a model with good
accuracy can be built for continuous kilns, a
clamp kiln model would involve a higher degree
of assumption and would bring less value to
clamp kiln managers.
The overarching principle of the tool relies on
the accurate estimation of each thermal energy
flow in the manufacturing process, i.e. in the
drying (if relevant) and firing processes.
Figure 12 represents the energy streams
quantified by the model.
Once these streams have been quantified, a
set of best practice opportunities are selected
based on the model outputs. Hence, instead of
a long list of energy saving opportunities, only
a subset of opportunities which best match the
areas of thermal energy losses are presented to
the user. Total potential savings are indicated in
term of energy (MJ) and money (Rand).
5. Thermal Energy Model
MINING Stock-piling
MIXING SETTING DRYING FIRING De-hacking
ShapingCrushing
Figure 11: Brick manufacturing process
Figure 12: Energy flows of the analysed system
Figure 13: Structure of the Excel tool› The purpose of the model is to generate an energy flow diagram (Sankey) as accurate as possible with the aim to recommend relevant energy saving opportunities to the brick factory manager
Thermal energy flows diagram of the system
Schematic Inputs Model - Outputs Best Practices Saved Data
Inputs Interface Best PracticesModel Outpus
Selection of plant’s main features
Data inputs
Required
Recommended
Optional
Breakdown of energyflows
Sankey diagrams
Model calculations
Assumptions
Plant’s SEC andbenchmark
Generated list of bestpractices
Description
Energy Savings
Rand savings
›
›
›
›››
›››
›
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201630 31
Energy Out kJ/hourkJ/kg
fired brick%
Energy to remove residual moisture 220,570 73 5.3%Energy for reactions in brick (dehydration, burn-off, vitrification) 603,103 200 14.4%Energy lost in flue gas (exhaust losses) 1,145,156 380 27.3%Energy from hot air extraction for heat recovery 321,509 107 7.7%Energy lost through kiln walls (structural losses) 1,071,105 355 25.5%Energy lost in kiln cars 110,250 37 2.6%Energy lost from hot fired bricks 499,369 166 11.9%Energy lost due to CO in flue gas 90,278 30 2.2%Energy unaccounted for 137,006 45 3.3%Total 4,198,347 1,392 100%
• The Inputs Sheet
The more data input into the model, the more accurate the outputs are. Therefore, it is encouraged to
provide as much data as possible. The various data has been broken down into three categories, each
one being monitored by a progress bar.
• The Outputs Sheet
The various energy flows for the firing process
(and drying process if relevant) are automatically
computed in a table based on the data given in
the inputs sheet. These data are also represented
in a diagram called “Sankey”, where each energy
flow is represented by an arrow whose height is
proportional to the amount of energy of the flow.
Required inputs include data on the production,
the mass and moisture content of bricks and the
fuel consumption. Recommended inputs include
data on the kiln dimensions, the temperature of
kiln walls, the temperature of bricks and kiln cars,
leaving the kiln and the temperature and flow rate
of the exhausts. Any recommended or optional
inputs not provided by the user is estimated by
the model using the required inputs and literature
values.
The model always indicates a certain percentage
of “Energy unaccounted for”. This represents
the amount of energy left that is not included in
any of the quantified energy flows. The energy
unaccounted for is typically positive, indicating that
some energy is lost through other ways, such as
non-insulated surfaces or sources of air ingress.
Each kiln has its own features and specificities that
cannot be quantified by a general model. A high
energy unaccounted for can also reflect inaccuracy
in the measurements or in the model. There will
always be some unaccountable energy and it is
normal in even the best audits to be + or – 10%.
The detailed model calculations and assumptions
made can be viewed on the same sheet.
• The Best Practices Sheet
Based on the model outputs, a list of best
practices is automatically generated for the
user. These selected best practices, grouped
into categories, target areas responsible for the
main thermal energy losses. For each category,
a comparison is made with best practice
plants and potential savings are calculated.
The model considers two best practice scenarios;
one being more stringent than the other, thus
indicating higher potential savings.
As a result, plant managers can use the tool to
identify set energy saving opportunities relevant
for their kiln. The business cases for these
opportunities can then be looked at in the long list
of best practices in Chapter 5.
Figure 14: The three categories of inputs
Table 13: Table showing an example of an energy balance for the firing process
To enable managers with limited data on their plant to use the model, inputs have been broken down into three categories. The completeness of each category indicated as below:
1.
2.
3.
Required inputs
Recommended inputs
Optional inputs
100%
32%
73%
Essential data needed torun the model
Optional data for increased accuracy
Data recommended to achievean acceptable level of accuracy
Any recommended or optional inputs which are not provided by the user will be assumed by the model. Categories of inputs include:
Production
Heat recovery
Kiln Cars
Exhaust gas
Kiln & Dryer
Bricks
Fuels
Model outputs
Kiln type
Dryer
Heat recovery
100%Required inputs
Recommended inputs 73%
32%Optional inputs
# fired bricks per year
Mass brick [kg]
Brick type 1 21,100,000 2.4 Brick type 2 13,300,000 2.6
34,400,000 2.5
Production
Kiln DryerSolid fuels Ton/yr Ton/yrCoal (anthracite)Coal (nuts)Coal (duff)
Fuels
Average mass of green bricks 3.00 kgAverage mass of dried bricks (before firing) 2.60 kg
Residual moisture of bricks before firing 2% (percentage)Temperature of fired bricks leaving kiln 100 °C
Bricks
Solid fuels LHV [MJ/kg] HHV [MJ/kg]Coal (anthracite)Coal (nuts)Coal (duff)
Fuels
Natural organic carbon content of brick 0.5% (% brick mass)
Dried brick temperature (leaving dryer) 80 °CDried brick temperature (entering kiln) 80 °C
Bricks
Kiln DryerHeight 3 3 mWidth 8 8 mLength 120 120 mAverage side wall external temperature 85 40 °C
Kiln & Dryer
Flue gas
Kiln cars
Heat recovery
Flue gas
Heat recovery
Kiln cars
ModelInputs
ModelOutputs
Negative "Energy unaccounted for" = Energy In is not enough
Fuel
Brick carbon
INPUT
Exhaust losses
Structural losses
Reactions in bricks
Heat loss from hot bricks and kiln cars
Residual Moisture
Energy unaccounted for
Heat recovery
CO in flue gasHot dried bricks
Firing process
ModelOutputs Drying process
Negative "Energy unaccounted for" = Energy In is not enough
Energy unaccounted for:E.g. uninsulated surfaces, structural losses, unburnt coal, CO in flue gas, hot air leaving from loading area, etc.
Fuel
Heat recovery
INPUT
Moisture
Exhaust lossesStructural losses
Heating bricks and cars
Energy unaccounted for
1. Identification of Energy Efficiency Opportunities in the South African Brick Market
Inputs1
Outputs2
Best Practices3
Energy Modelling Tool: how does it work ?
1. Input of plant-specific data2. Generation of thermal energy flow diagrams3. Identification of suitable best practices &
assessment of potential energy savings
The three-step model is designed to analyse a wide range of brick kiln types. The more data is input into the model, the more accurate will be the outputs. If some data are not specified, the model will estimate them based on specified inputs and using industry averages and literature values.
Best Practices
Thermal Efficiency: Tunnel kiln
Your plant 3.0Including dryer 3.7
Best practice plant 0.8 (Int. benchmark)
Best practice plant 2.0 (Model calculation)
Potential Energy Saving
1.1MJ / kg
Scenario
35%
Potential Cost Saving
Rand / year16,119,530
Units
Reduce moisture content of dried bricks entering kilnEnsure bricks are fully dried (below 2% moisture content) prior to entering the kiln.Minimise the standing time between dryer and kiln to avoid the re-absorption of moisture.
Moisture 0.00% 2.00% 118 1,847,490
Energy saving opportunities for your plant Best practice Your plantEnergy saving
[kJ/kg]Cost saving[Rand/year]
Improve combustion efficiencyMeasure kiln O2 profile and use to adjust the burner air, kiln draft and rapid cooling air to return to optimum setting.Carry out ongoing daily visual checks on kiln burners to ensure complete combustion at point of entry. Use of best quality coal available locally with consistent calorific value and consistent particle size consistent with firing system in place.Add fuel only to the kiln when it will quickly combust, i.e. when red heat can be seen or the temperature is above 800°C.Oil burners: optimise pulse time and droplet size, drops should combust before reaching kiln deck but not prematurely.
CO in flue gas 0.00% 0.01% 3 47,503
Reduce heat loss through kiln structure
Ensure that the stoker pots on permanent roofed kilns are capped to avoid heat losses and are sufficiently numerous to allow an even distribution of fuel into the firing zone.
Insulation of hot air pipework & ductwork. In general maintain hot air ductwork insulation levels to a minimum of 50mm for temperatures below 200oC and 100mm at higher temperatures. Ensuring all kiln walls and roofs are maintained in good condition and well insulated.Minimising the time the exhaust damper is left open during new brick setting.Fitting exit doors to reduce unwanted additional air on older kilns. Ensure all doors are well sealed and door control management during pushing is effective. Reduce the air flow into and out of the roof cooling space (where it exists) to reduce heat loss from the kiln.
Heat loss [kJ/kg] 50 810 760 11,901,061
Reduce excess air and air ingress levelsReduce exhaust fan speed to reduce air ingress and reduce heat loss through exhaust.
Reduce excess combustion air by reducing supply pressure or closing damper positions on individual burners.Use a combustion analyser to measure and minimise excess air levels.
Reduce kiln airflow levels by reducing exit contravec fan and cooling fan speeds where the brick exit temperature is already low. Use PID controller of air movement fans.
Excess air 200.00% 260.06% 113 1,765,046
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201632 33
5.3. BestPractice Categories
The long list of best practices on the thermal
energy side has been broken down into 10
categories. Each category is tested based on a
specific criteria. If, for the tested criteria, the model
indicates a higher value than the corresponding
expected value for best practice plants, the
category is highlighted and a list of related energy
saving opportunities is indicated. For example, the
specific criteria for Category 3 is the amount of
CO (carbon monoxide) in the flue gas. If the model
indicates a CO content above the best practice
value of 500ppm, a list of opportunities on how to
improve combustion efficiency is indicated.
The table below summarises the 10 sections
and their tested criteria. Typical observations and
causes that can corroborate the model’s analysis
are also indicated.
Note that the table only shows the 10 sections, but
no details on the best practices in each section is
given. The full list of best practices can be found
in Chapter 5.
# Category Observations CauseTested criteria
Best practice
1
Reduce moisture
content of dried
bricks entering kiln
• Shattered, broken
or cracked bricks
• Excessive
dampness or
condensation in
the stack
• Moisture content of
bricks is too high
Moisture
level [%]2%
2Reduce moisture
content of coal
• Moisture content of
fuel is too highMoisture
level [%]2%
3
Improve
combustion
efficiency
• Black smoke
emitted from
chimney stack
• Carbon monoxide
measured in chim-
ney stack
• Combustion taking
place at too low
temperatures
• Insufficient
combustion air
reaching the fuel
once it is above the
combustion point,
e.g. brick seeting is
too dense and air
cannot reach the
fuel for combustion
• Moisture content of
bricks and/or fuel is
too high
CO in flue
gas [ppm]500
4Improve efficiency of heating
Variable quality:• Darker brick colours, hard,
low moisture content, partially molten
• Lighter brick colours, weak brick, high moisture content
• Multi coloured darker bricks, possible black core and black surface. Some signs of melting
Poor temperature control:• Different parts of the
same chamber or kiln car at different temperatures
• Peak temperature variable resulting in some bricks being over fired and some under fired
Variable quality:• Bricks over fired or
underfired• Bricks subject to
reducing conditionsPoor temperature control:• Uneven fuel distribution• Poor air circulation and
exhaust pathways• Kiln under too much
suction• Walls and roof in poor
repair
SEC[MJ/kg]
Depends on kiln type
5
Reduceexcess air and air in-gress levels
• Low exhaust stack temperatures & high exhaust flow rates
• Too much air being admitted into the kiln resulting in too much hot air leaving the kiln through the exhaust
Excess air level [%]
200%
6
Reduce heat loss through kilnstructure
• Hot kiln walls and roof
• Uncontrolled air leaking into or out of the kiln though walls or roof
• Poorly maintained walls and roof
• Kiln under too much suction
Heat loss through walls[kJ/kg]
200 kJ/kg
7
Reduce temperature of bricks leaving the kiln
• Bricks are too hot at the kiln exit making them difficult to handle and wasting the heat energy that they contain
• The kiln or the firing cycle is too short is too short meaning there is insufficient time to cool the bricks properly and recover all the heat within the kiln
• Back flow of hot air from the firing zone into the cooling zone
• Brick setting is too dense to allow cooling air to reach and cool within the entire brick setting
Brick tempera-ture [°C]
100 °C
8
Reduce waste levels by improving theconsistency of the raw materials
• High number of wasted bricks
• Inconsistent particle size distribution
• Inconsistent moisture content Wastage
[%] 2%
9 Heatrecovery
Using heat recovery
Yes
10Energyunaccounted for
• All other energy losses that cannot be quantified in the above sections
• Uninsulated surfaces (ducts, lids, etc.), unburnt coal, hot air leaving from loading area, other sources of air egress, etc.
Other losses [%]
5%
Table 14: Summary of the 10 best practice categories used in the model, as well as related observations, causes, tested criteria and best practice values
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201634 35
5.4. Case Studies
In this section, we will briefly analyse three case
studies. The first case study is a tunnel kiln in the
UK and the second and third case studies are
South African tunnel kiln and VSBK respectively.
5.4.1. Tunnel Kiln in the UK
This is an old tunnel kiln located in England using
natural gas as the only fuel. It has an external
dryer using hot air recovered from the kiln. All
required inputs were provided, as well as 73% of
recommended inputs and 32% of optional inputs.
The outputs for the firing and drying processes are
presented below (tables and Sankey diagrams).
From the energy balance above, some observations
can already be made. Looking at the firing process,
the energy lost through the kiln walls is very high
and something should be done to reduce the
structural losses. (Note that structural losses are
the most difficult to estimate accurately due to
large variations of the external wall temperatures).
Exhaust losses are also high, however it is expected
that exhaust gas accounts for about 20% of the
total energy. We can also observe that very little
energy is lost in kiln cars and fired bricks, indicating
that they are leaving the kiln are reasonable
temperatures. The very low energy lost due to CO
in flue gas reflects a good combustion efficiency,
which is typically expected with high excess air.
Finally, about 30% of the energy is hot air recovered
and sent to the dryer. Looking at the dryer’s Sankey
diagram, we see that only 41.1% of the input
energy is required to dry the bricks. Therefore, it is
possible that too much hot air is sent to the dryer
and energy could be saved by reducing the amount
of fresh air blown in the kiln and then recovered.
Next, we look at the Best Practice Sheet. The SEC
(Specific Energy Consumption) of the firing process
is 2.9MJ/kg, compared to best practice tunnel kilns
at 0.8MJ/kg based on international benchmarks,
which shows that this kiln is a long way from being
the most efficient one. The model calculates that,
under a conservative scenario, 23% or 0.7MJ/kg
of energy savings have been identified, which could
bring the kiln’s SEC to 2.2MJ/kg. This corresponds
to a saving of nearly R11 million per year.
Four areas are highlighted where tested criteria
are above expected values for best practice kilns:
- Improving efficiency of heating (SEC of 2.9MJ
kg vs. 0.8MJ/kg)
- Reducing excess air and air ingress levels
(excess air of 260% vs. 200%)
- Reducing heat loss through the kiln structure
(heat loss of 783kJ/kg vs. 200kJ/kg)
- Energy unaccounted for (11% vs. 5%)
For each of these four categories a list of
opportunities is given to suggest how these savings
could be achieved (details are not provided here).
• Firing Process
Figure 16: Model results for the firing process of the UK tunnel kiln example displayed in tables and in a Sankey diagram
• Drying Process
Figure 17: Model results for the drying process of the UK tunnel kiln example displayed in tables and in a Sankey diagram.
%#%
"
Energy Out kJ/hourkJ/kg
fired brick%
Energy to remove brick moisture 3,893,779 389 41.1%Energy lost in flue gas (exhaust losses) 384,919 38 4.1%Energy lost through dryer walls (structural losses) 1,061,454 106 11.2%Energy lost in heating bricks 600,636 60 6.3%Energy lost in heating kiln cars 75,042 8 0.8%Energy unaccounted for 3,467,162 347 36.6%Total 9,482,992 948 100%
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201636 37
5.4.2. Tunnel Kiln in South Africa
This is a tunnel kiln located in South Africa using
heavy fuel oil and a waste product as fuels. It has an
external dryer using hot air recovered from the kiln.
All required inputs were provided, as well as 91% of
recommended inputs and 63% of optional inputs.
The outputs for the firing and drying processes are
presented below (tables and Sankey diagrams).
• Firing Process
Figure 18: Model results for the firing process of the South African tunnel kiln example displayed in tables and in a
Sankey diagram
From the above energy balance, it can be observed
that the structural losses are low and are not an
area of concern. Most of the energy is found in
the exhausts and in the heat recovered for the
dryer. In this example, the energy unaccounted
for is negative, which means that either the input
energy is lower than it should be, or measurements
are inaccurate. Looking at the dryer’s Sankey
diagram, one can observe that the positive energy
unaccounted for is almost equivalent to the negative
energy unaccounted for in the firing process. It is
therefore likely that the heat recovered from the
kiln is actually lower (e.g. inaccurate flow rate).
Similar to the UK tunnel kiln, it is possible that too
much hot air is sent to the dryer and energy could
be saved by reducing the amount of fresh air blown
in the kiln and then recovered.
In the Best Practice Sheet, the SEC of the firing
process is calculated at 2.8MJ/kg (note: the SEC
is based on the number of saleable bricks and
not the total number of fired bricks), compared to
best practice tunnel kilns at 0.8MJ/kg based on
international benchmarks. The model calculates
that, under a conservative scenario, 30% or
0.8MJ/kg of energy savings have been identified,
which could bring the kiln’s SEC to 2.0MJ/kg. This
corresponds to a saving of nearly R6 million per
year.
Five areas are highlighted where tested criteria are
above expected values for best practice kilns:
- Reducing the moisture content of dried bricks
entering the kiln (moisture of 3% vs. 2%)
- Improving combustion efficiency (0.09% of CO
in flue gas vs. 0.05%)
- Improving efficiency of heating (SEC of 2.8MJ
kg vs. 0.8MJ/kg)
- Reducing excess air and air ingress levels
(excess air of 347% vs. 200%)
- Reducing waste levels (10% vs. 2%)
For each of these five categories a list of
opportunities is given for how these savings could
be achieved (details are not provided here).
%!
"
%!
• Drying Process
Figure 19: Model results for the drying process of the South African tunnel kiln example displayed in tables and in a
Sankey diagram
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201638 39
5.4.3. Vertical Shaft Brick Kiln (VSBK) in South Africa
This is a VSBK located in South Africa using coal (nuts and duff) as main fuel. No information is given
on the dryer. All required inputs were provided, as well as 83% of recommended inputs and 43% of
optional inputs. The outputs for the firing process are presented below (tables and Sankey diagram).
• Firing Process
Figure 20: Model results for the firing process of the South African VSBK example displayed in tables and in a Sankey
diagram
In this example, the exhausts losses are low, which
reflects very good use of the heat contained in
the exhaust, which is typically the case for VSBK
designs. The main area of losses by far is through
the kiln walls (note: structural losses are typically
hard to estimate accurately and depend largely on
the number of measurements made. In this case,
only one average temperature was given, which is
insufficient to provide an accurate estimation).
In the Best Practice Sheet, the SEC of the firing
process is calculated at 1.1MJ/kg, which is similar
to best practice plants based on international
benchmarks. The model calculates that, under a
conservative scenario, 32% or 0.4MJ/kg of energy
savings have been identified, which could bring
the kiln’s SEC to 0.7MJ/kg. This corresponds to a
saving of R0.9 million per year.
Five areas are highlighted where tested criteria are
above expected values for best practice kilns:
- Reducing the moisture content of coal
(moisture of 2.4% vs. 2%)
- Improving combustion efficiency (0.19% of CO
in flue gas vs. 0.05%)
- Reducing excess air and air ingress levels
(excess air of 375% vs. 200%)
- Reducing heat loss through the kiln structure
(heat loss of 501kJ/kg vs. 200kJ/kg)
- Energy unaccounted for (15.6% vs. 5%)
For each of these five categories a list of
opportunities is given for how these savings could
be achieved (details are not provided here).
- -1,118
$
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201640 41
6.1. IntroductionIn this chapter, best practice opportunities are
presented that have the potential to reduce the
energy consumption of the kiln and improve quality.
We have selected three areas that operators
should be continually seeking to improve in their
kiln operations:
• Energy consumption;
• Quality;
• Environmental impact.
The analysis of the best practices below showed
that any actions taken to improve energy
consumption will also improve the quality of product
increasing profits and reduce the environmental
impact improving the conditions for workers and
the local community.
6.2. List of Best PracticesThe list of opportunities below has been produced
to assist brick manufactuers to determine the most
appropriate recommendations to improve their
brick making process.
The list contains 70 energy saving opportunities,
which have been selected from a long list of
about 150 opportunities from various sources
including energy audits conducted at South
African brick yards, manufacturers, suppliers
and Carbon Trust. All opportunities were rated
for production improvement, energy saving,
ease of implementation, cost of implementation,
replicability and payback. Based on these criteria,
the master list was refined twice to get to the final
list of 70 best practices.
Using Chapter 5, you may have already determined
an approximate heat balance for your kiln to identify
where you are losing the largest amount of heat
from the kiln. If you have used the thermal energy
tool, you should already have identified a subset of
best practices from the list below which are most
relevant for your plant. In this list, each opportunity
has been evaluated to inform brick plant managers
on the estimated savings that could be achieved,
as well as the estimated investment required and
payback period. A number of assumptions were
made to obtain these figures. Therefore, savings,
investments and payback periods will be different
for every factory, but it should indicate the right
scales that can be expected for each opportunity.
All opportunities were assessed based on a plant
producing 30 million bricks per year.
Most of the measures identified in this section
are applicable to all fixed kilns and about half
of them are applicable to clamp kilns as well.
This is indicated in the first column.
6. Opportunities
Figure 21: Refinement of the best practice list
Kiln
Ty
peE
nerg
y S
avin
g O
ppor
tuni
ties
Eas
e of
im
plem
enta
-tio
n
Bus
ines
s ca
ses
base
d on
30
mill
ion
bric
ks/y
ear
Est
imat
ed
ener
gy
savi
ngs
Est
imat
ed
savi
ngs
Est
imat
ed
Inve
st-
men
t
Est
imat
ed
payb
ack
1.
Impr
ovin
g co
mbu
stio
n ef
ficie
ncy
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/Ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Cla
mp
At
clam
p ig
nitio
n &
sta
rt u
p, e
nsur
e fu
el is
eve
nly
dist
ribut
ed w
ithin
the
fire
box
as
wel
l as
the
skin
kel l
ayer
s. U
se f
iring
cha
nnel
s to
ens
ure
effic
ient
com
bust
ion
for
light
ing
and
cont
rolli
ng a
ir flo
w in
to th
e cl
amp
once
firin
g is
und
erw
ay.
easy
3,3
00
,00
01
21
,00
01
0,0
00
0.1
Fixe
d &
Cla
mp
Use
of
be
st
qual
ity
coal
av
aila
ble
loca
lly
with
co
nsis
tent
ca
lorif
ic
valu
e an
d
cons
iste
nt p
artic
le s
ize, c
onsi
sten
t with
firin
g sy
stem
in p
lace
.ea
sy4
,80
0,0
00
17
6,0
00
10
,00
00
.1
Fixe
dA
dd fu
el o
nly
to th
e ki
ln w
hen
it w
ill q
uick
ly c
ombu
st, i
.e. w
hen
red
heat
can
be
seen
or th
e te
mpe
ratu
re is
abo
ve 8
00o C
.ea
sy6
,30
0,0
00
23
1,0
00
50
,00
00
.2
Fixe
dO
il bu
rner
s: o
ptim
ise
puls
e tim
e an
d dr
ople
t si
ze,
drop
s sh
ould
com
bust
bef
ore
reac
hing
kiln
dec
k bu
t not
pre
mat
urel
y.m
oder
ate
7,5
00
,00
06
98
,00
01
,00
0,0
00
1.4
Fixe
dC
arry
out
ong
oing
dai
ly c
heck
on
kiln
bur
ners
to
ensu
re c
ompl
ete
com
bust
ion
at
poin
t of e
ntry
. ea
sy1
,80
0,0
00
20
0,0
00
00
.0
Fixe
dM
easu
re k
iln O
2 p
rofil
e an
d us
e to
adj
ust t
he b
urne
r ai
r, ki
ln d
raft
and
rap
id c
oolin
g
air t
o re
turn
to o
ptim
um s
ettin
g.m
oder
ate
1,8
00
,00
02
00
,00
02
00
,00
01
.0
2. I
mpr
ovin
g he
atin
g ef
ficie
ncy
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/Ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dA
dditi
on o
f in
tern
al f
uel (
carb
on)
to m
inim
ise
the
amou
nt o
f ex
tern
al f
iring
of
solid
fuel
requ
ired.
easy
3,0
00
,00
08
02
,00
02
0,0
00
0.0
Fixe
d
Mai
ntai
ning
a s
tead
y ris
e in
tem
pera
ture
thro
ugh
the
clea
n an
d ef
ficie
nt c
ombu
stio
n
of fu
el. C
ontr
olle
d co
ntin
uous
firin
g of
kiln
s is
pre
fera
ble
to o
ver-
fuel
ling
the
kiln
. For
exam
ple
inst
all P
LCs
& P
ID c
ontr
olle
rs o
n fir
ing
equi
pmen
t.
easy
12
,00
0,0
00
43
9,0
00
25
0,0
00
0.6
Final list
1st
Edit
Master list
10 Energy audits Manufacturers Suppliers UK Carbon Trust Other industry sources
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201642 43
Fixe
d &
Cla
mp
Opt
imis
atio
n of
set
ting
patt
ern
such
tha
t al
l com
bust
ion
air
can
reac
h al
l fue
l and
that
hot
gas
es c
an re
ach
all t
he b
ricks
.ea
sy4
,20
0,0
00
15
4,0
00
20
,00
00
.1
Fixe
dE
nsur
e bu
rner
dilu
tion
air
is m
aint
aine
d to
a m
inim
um o
n dr
yer
burn
ers,
use
reci
rcul
atio
n ai
r ins
tead
.ea
sy1
,80
0,0
00
20
0,0
00
00
.0
Fixe
d
Che
ck t
hat
the
exha
ust
fan
spee
d re
duce
s w
ith k
iln t
herm
al in
put
i.e. e
xhau
st f
an
mod
ulat
es in
acc
orda
nce
with
the
fue
l inp
ut a
nd c
lose
s do
wn
durin
g a
push
, if
it
does
n’t,
it m
eans
fres
h co
ld a
ir is
bei
ng p
ulle
d in
to th
e ki
n w
astin
g he
at.
mod
erat
e1
,80
0,0
00
20
0,0
00
00
.0
Fixe
d &
Cla
mp
Incr
easi
ng p
erfo
ratio
n si
ze o
f ex
trud
ed b
ricks
con
sist
ent
with
loc
al s
tand
ards
to
redu
ce f
iring
ene
rgy
requ
irem
ent
and
impr
ove
air
flow
thr
ough
bric
k se
ttin
g. (
Bes
t
prac
tice
exam
ple
incr
ease
from
25
% to
40
%).
diff
icul
t3
,00
0,0
00
30
0,0
00
1,0
00
,00
03
.3
Fixe
d
On
TVA
/Hof
fman
typ
e ki
lns,
ens
ure
that
a g
ood
seal
exi
sts
in t
he p
rehe
at s
ectio
n
and
is a
s ai
r tig
ht a
s po
ssib
le s
o th
at c
old
air
is n
ot p
ulle
d th
roug
h th
e br
icks
by
the
exha
ust
fan.
(B
est
prac
tice
exam
ple
assu
mes
10
% o
f ex
haus
t is
fro
m c
old
air
thro
ugh
the
preh
eat h
eat e
xcha
nge
by 2
0o C
. The
re is
als
o a
pow
er s
avin
g.)
easy
1,2
00
,00
01
30
,00
00
0.0
Fixe
dIn
crea
se re
circ
ulat
ion
rate
s in
the
drye
rs w
here
pos
sibl
e.ea
sy1
,00
5,0
00
5,1
06
,00
02
5,0
00
0.0
Fixe
dU
se o
f hig
h ve
loci
ty re
circ
ulat
ion
(e.g
. con
es) i
n th
e dr
yer t
o im
prov
e he
at d
istr
ibut
ion
in c
ham
ber d
ryer
s.di
ffic
ult
75
0,0
00
84
,00
02
50
,00
03
.0
3. R
educ
ing
exce
ss a
ir an
d ai
r ing
ress
leve
lsS
avin
gs
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dR
educ
e ex
haus
t fan
spe
ed b
y 1
0%
to re
duce
hea
t los
s th
roug
h ex
haus
t.ea
sy3
,52
4,0
00
37
2,0
00
00
.0
Fixe
dR
educ
e ki
ln a
irflo
w le
vels
by
switc
hing
off
con
trav
ec fa
ns a
nd re
duci
ng in
put o
f low
pres
sure
con
trav
ec fa
ns w
here
bric
k ex
it te
mpe
ratu
re is
alre
ady
low
.m
oder
ate
4,4
09
,00
04
66
,00
00
0.0
Fixe
dR
educ
e ex
cess
com
bust
ion
air
by r
educ
ing
supp
ly p
ress
ure
or c
losi
ng d
ampe
r
posi
tions
on
indi
vidu
al b
urne
rs.
mod
erat
e5
,36
3,0
00
34
3,0
00
25
0,0
00
0.7
Fixe
d
Impr
ove
cool
ing
zone
bal
ance
by
redu
cing
the
flo
w t
hrou
gh t
he e
xit
cont
rave
c an
d
the
inje
ctio
n co
olin
g by
10
% to
red
uce
the
egre
ss o
f ho
t air
from
the
cool
ing
zone
into
the
firin
g zo
ne. U
se P
ID c
ontr
olle
r of
air
mov
emen
t fan
s to
mai
ntai
n a
cons
tant
pres
sure
in th
e co
olin
g zo
ne a
nd a
ny h
eat r
ecov
ery
off t
ake.
easy
2,6
89
,00
02
84
,00
01
25
,00
00.
4
Fixe
dU
se a
com
bust
ion
anal
yser
to m
easu
re a
nd m
inim
ise
exce
ss a
ir le
vels
.m
oder
ate
--
--
4. R
educ
ing
tem
pera
ture
of b
ricks
leav
ing
cont
inuo
us k
ilns
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dE
nsur
e br
icks
leav
ing
the
kiln
are
coo
led
to b
elow
10
0°C
and
the
heat
is re
cove
red
into
the
kiln
or d
ryer
.m
oder
ate
6,0
00
,00
06
50
,00
02
50
,00
00
.4
5. R
educ
ing
heat
loss
thro
ugh
kiln
str
uctu
reS
avin
gs
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d
Insu
latio
n of
hot
air
pipe
wor
k &
duc
twor
k. I
n ge
nera
l, m
aint
ain
hot
air
duct
wor
k
insu
latio
n le
vels
to a
min
imum
of 5
0m
m fo
r tem
pera
ture
s be
low
20
0o C a
nd 1
00
mm
at h
ighe
r tem
pera
ture
s.
easy
72
0,0
00
46
,00
02
0,0
00
0.4
Cla
mp
Sco
ving
(sm
earin
g) th
e ou
tsid
e w
alls
of a
cla
mp
kiln
with
cla
y. T
his
is g
ood
prac
tice
but
ofte
n no
t em
ploy
ed w
here
the
sca
le o
f cl
amp
kiln
s ge
ts q
uite
lar
ge.
As
the
amou
nt o
f ca
rbon
in t
he b
ricks
is d
eter
min
ed b
efor
e sc
ovin
g, t
he p
ract
ice
may
not
redu
ce e
nerg
y us
age
dire
ctly
but
inst
ead,
lim
it th
e im
pact
of
win
d an
d ra
in o
n th
e
bric
k qu
ality
and
impr
ove
yiel
ds.
mod
erat
e6
,60
0,0
00
20
4,0
00
50
,00
00
.2
Fixe
dE
nsur
ing
all k
iln w
alls
and
roof
s ar
e m
aint
aine
d in
goo
d co
nditi
on a
nd w
ell i
nsul
ated
.ea
sy2
,40
0,0
00
74
,00
05
0,0
00
0.7
Fixe
dM
inim
isin
g th
e tim
e th
e ex
haus
t da
mpe
r is
left
ope
n du
ring
new
bric
k se
ttin
g in
a
VS
BK
.ea
sy8
00
,00
09
0,0
00
00
.0
Fixe
dFi
ttin
g ex
it do
ors
to r
educ
e un
wan
ted
addi
tiona
l air
on o
lder
kiln
s. E
nsur
e al
l doo
rs
are
wel
l sea
led
and
door
con
trol
man
agem
ent d
urin
g pu
shin
g is
eff
ectiv
e.ea
sy1
,20
0,0
00
13
5,0
00
50
0,0
00
3.7
Fixe
d
Ens
ure
that
the
sto
ker
pots
on
perm
anen
t ro
ofed
kiln
s ar
e ca
pped
to
avoi
d he
at
loss
es a
nd a
re s
uffic
ient
ly n
umer
ous
to a
llow
an
even
dis
trib
utio
n of
fue
l int
o th
e
firin
g zo
ne.
easy
--
--
Fixe
dR
educ
e th
e ai
r flo
w in
to a
nd o
ut o
f the
roof
coo
ling
spac
e w
here
it e
xist
s to
redu
ce
heat
loss
from
the
kiln
.ea
sy6
,89
7,0
00
44
1,0
00
25
0,0
00
0.6
6. H
eat r
ecov
ery
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dU
sing
hea
t ex
chan
ger
in t
he e
xhau
st t
o pr
e-he
at H
FO t
o el
imin
ate
the
elec
tric
al
heat
ing
syst
em.
mod
erat
e2
36
,00
04
7,0
00
90
,00
01
.9
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201644 45
Fixe
dIn
stal
l an
exha
ust h
eat e
xcha
nger
to p
rehe
at c
ombu
stio
n ai
r for
tunn
el k
iln o
r dry
ers.
diff
icul
t1
1,7
01
,00
01
,23
6,0
00
3,7
50
,00
03
.0
Fixe
dU
se o
f ho
t ai
r fr
om t
he k
iln c
oolin
g sy
stem
s as
pre
heat
ed c
ombu
stio
n ai
r. Fo
r
exam
ple
roof
spa
ce a
nd k
iln c
ar c
oolin
g ai
r.m
oder
ate
14
,82
6,0
00
1,5
65
,00
06
25
,00
00
.4
7. U
pgra
ding
kiln
tech
nolo
gyS
avin
gs
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d &
Cla
mp
Rep
lace
the
cur
rent
Cla
mp
Kiln
with
a f
ixed
kiln
of
som
e ki
nd (
e.g.
VS
BK
, Zig
-zag
,
TVA
, Tun
nel K
iln e
tc.).
diff
icul
t2
52
,00
0,0
00
7,7
54
,00
01
8,0
00
,00
02
.3
8. E
nerg
y m
anag
emen
t & m
easu
rem
ent
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d &
Cla
mp
Mon
itor f
uel a
nd p
ower
con
sum
ptio
n in
the
min
e to
sel
ect t
he m
ost e
ffic
ient
min
ing
met
hod.
With
con
trac
tors
hav
e th
em p
urch
ase
thei
r ow
n di
esel
to e
ncou
rage
ene
rgy
effic
ienc
y in
min
ing
oper
atio
ns.
easy
--
--
Fixe
d &
Cla
mp
Ado
ptio
n of
Ene
rgy
Man
agem
ent S
yste
m (I
SO
50
00
1 o
r sim
ilar)
.m
oder
ate
--
--
Fixe
d &
Cla
mp
Impr
oved
met
erin
g on
fuel
con
sum
ptio
n.ea
sy2
,25
0,0
00
26
1,0
00
38
0,0
00
1.5
Fixe
dP
roce
ss
optim
isat
ion:
op
erat
e at
hi
gher
th
roug
hput
s at
th
e ki
ln
and
high
er
oper
atio
nal e
quip
men
t eff
ectiv
enes
s.ea
sy3
1,1
58
,00
03
,81
0,0
00
00
.0
Fixe
d &
Cla
mp
Rip
nex
t min
ing
area
at c
oncl
usio
n of
min
ing
cam
paig
n to
allo
w n
atur
al fo
rces
(win
d,
rain
& s
un) t
o br
eak
dow
n m
ater
ials
bef
ore
min
ing.
easy
--
--
Fixe
d &
Cla
mp
Use
of r
ecen
t mod
el e
arth
-mov
ing
mac
hine
ry.
mod
erat
e-
--
-
Fixe
d &
Cla
mp
Use
of r
ecen
t mod
el fo
rklif
ts a
nd o
ptim
isat
ion
of p
rodu
ct m
ovem
ent.
Bus
ines
s ca
se
with
two
old
mac
hine
s re
plac
ed b
y on
e ne
w m
achi
ne.
mod
erat
e1
,53
0,0
00
53
9,0
00
92
0,0
00
1.7
Fixe
d
Impr
ovin
g qu
ality
thr
ough
tem
pera
ture
mea
sure
men
ts:
use
bulle
rs r
ings
to
as-
sess
mor
e ac
cura
tely
pea
k te
mpe
ratu
re v
aria
tion
with
in t
he k
iln,
use
addi
tiona
l
perm
anen
t or
tem
pora
ry t
herm
ocou
ples
. Use
the
se r
esul
ts t
o re
duce
tem
pera
ture
varia
tion
with
in p
rehe
at, f
iring
& c
oolin
g zo
nes.
mod
erat
e-
--
-
Fixe
dU
se a
man
omet
er to
mea
sure
and
con
trol
dra
ught
at t
he k
iln e
xhau
st.
easy
--
--
9. R
educ
ing
moi
stur
e co
nten
t of d
ried
bric
ks e
nter
ing
kiln
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d &
Cla
mp
Ens
ure
bric
ks a
re f
ully
drie
d pr
ior
(bel
ow 2
% m
oist
ure
cont
ent)
prio
r to
ent
erin
g th
e
kiln
.ea
sy4
,00
0,0
00
45
0,0
00
00
.0
10
. Red
ucin
g te
mpe
ratu
re o
f kiln
car
s le
avin
g co
ntin
uous
kiln
sS
avin
gs
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dM
aint
aini
ng k
iln c
ar s
eals
in o
ptim
um c
ondi
tion
thro
ugh
plan
ned
or c
ondi
tion
base
d
mai
nten
ance
.m
oder
ate
1,8
00
,00
02
00
,00
02
00
00
0/y
ear
1.0
Fixe
dR
educ
e th
e th
erm
al m
ass
of k
iln c
ar d
ecks
usi
ng li
ghtw
eigh
t ref
ract
ory
or fi
bre.
mod
erat
e1
5,0
00
,00
01
,39
6,0
00
3,8
25
,00
02
.7
11
. Red
ucin
g w
aste
leve
ls b
y im
prov
ing
the
cons
iste
ncy
of t
he r
aw
mat
eria
ls
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d &
Cla
mp
Impr
ovem
ent
of r
aw m
ater
ial
mix
es b
y in
corp
orat
ing
smal
l qu
antit
ies
of i
mpo
rted
mat
eria
ls. T
est m
ixes
firs
t in
the
labo
rato
ry p
rior t
o in
corp
orat
ion.
mod
erat
e5
,55
0,0
00
46
7,0
00
50
0,0
00
1.1
Fixe
d &
Cla
mp
Impr
ovem
ent o
f sou
ring
prac
tice
afte
r min
ing
thro
ugh
stoc
kpili
ng p
ract
ices
.m
oder
ate
2,8
50
,00
02
66
,00
06
00
,00
02
.3
Fixe
d &
Cla
mp
Obt
ain
a co
nsis
tent
par
ticle
size
dis
trib
utio
n th
roug
h si
eve
anal
ysis
and
adj
ustm
ent o
f
rolle
r gap
s or
raw
mat
eria
l ble
nd.
mod
erat
e2
,17
5,0
00
15
3,0
00
25
0,0
00
1.6
Fixe
d &
Cla
mp
Ens
ure
a co
nsis
tent
m
oist
ure
cont
ent
thro
ugh
prop
er
stoc
kpili
ng
and
mix
ing.
Mea
sure
moi
stur
e co
nten
t tw
ice
daily
usi
ng d
irect
met
hods
or u
sing
pen
etro
met
er.
easy
2,1
75
,00
01
53
,00
02
00
,00
01
.3
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201646 47
Fixe
d &
Cla
mp
Sca
lpin
g of
und
ersi
ze m
ater
ial
mix
usi
ng s
cree
ns t
o av
oid
mat
eria
l un
nece
ssar
ily
goin
g th
roug
h pr
epar
atio
n pl
ant.
mod
erat
e3
45
,00
05
5,0
00
30
0,0
00
5.5
Fixe
d &
Cla
mp
Usi
ng b
ody
addi
tives
to im
prov
e qu
ality
.ea
sy2
,31
3,0
00
45
,00
05
0,0
00
1.1
Fixe
d &
Cla
mp
Usi
ng b
ody
addi
tives
to re
duce
firin
g te
mpe
ratu
re.
easy
3,0
00
,00
04
0,0
00
15
0,0
00
3.8
12
. Low
car
bon
alte
rnat
ive
fuel
s an
d m
ater
ials
Sav
ings
[MJ/
year
]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
d &
Cla
mp
Add
ition
of
w
aste
pr
oduc
ts
(e.g
. se
wag
e sl
udge
, pa
per
pulp
) th
at
impr
ove
wor
kabi
lity/
extr
udab
ility
of t
he c
olum
n, b
enef
its in
clud
e de
mat
eria
lisat
ion,
low
er ra
w
mat
eria
l usa
ge, l
ight
er b
ricks
, som
e fu
ellin
g be
nefit
, and
low
er e
xtru
sion
am
ps.
mod
erat
e1
04
,00
01
,53
1,0
00
50
0,0
00
0.3
Fixe
d &
Cla
mp
Co
firin
g ki
lns
with
syn
gas,
bio
gas
or p
yrol
ysis
allo
win
g fu
el s
witc
hing
to
give
flexi
bilit
y.di
ffic
ult
02
40
,00
02
,00
0,0
00
8.3
Fixe
d &
Cla
mp
Ope
n up
bric
k bo
dy a
nd re
duce
fire
d m
ass
thou
gh th
e ad
ditio
n of
ligh
twei
ght w
aste
mat
eria
ls a
nd b
iom
ass
mat
eria
l.m
oder
ate
01
,51
5,0
00
50
0,0
00
0.3
13
. Pow
erS
avin
gs
[MW
h/ye
ar]
Sav
ings
[Ran
d/ye
ar]
Inve
stm
ent
[Ran
d]
Pay
back
[Yea
rs]
Fixe
dFa
n sy
stem
opt
imis
atio
n (t
ype
of fa
ns, d
e-co
mm
issi
on o
f som
e fa
ns, e
tc.).
Eas
y-
--
-
Fixe
dC
onve
rt a
ir m
ovem
ent
fan
mot
ors
to v
aria
ble
spee
d ty
pe o
r fit
sep
arat
e va
riabl
e
spee
d dr
ive
(VS
D).
Eas
y2
,03
8,0
00
2,3
44
,00
05
22
,00
00
.2
Fixe
d &
Cla
mp
Pow
er fa
ctor
cor
rect
ion
to re
duce
max
imum
dem
and
char
ges
and
resi
stan
ce lo
sses
.E
asy
--
--
Fixe
d &
Cla
mp
Tarif
f op
timis
atio
n th
roug
h sh
iftin
g op
erat
ions
out
side
of
peak
hou
rs,
espe
cial
ly
durin
g th
e hi
gh d
eman
d se
ason
.E
asy
--
--
Fixe
d &
Cla
mp
Max
imum
de
man
d m
anag
emen
t th
roug
h im
plem
enta
tion
of
a re
al
time
mea
sure
men
t and
mon
itorin
g sy
stem
to c
ontr
ol m
axim
um d
eman
d ch
arge
s.E
asy
07
8,0
00
15
,00
00
.2
Fixe
d &
Cla
mp
Aut
omat
ed &
pha
sed
switc
h of
f of p
lant
whe
n pr
oduc
tion
ceas
es.
Eas
y6
00
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South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201648 49
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln, etc.)
Development
Description
Clamp kilns are by a large margin the most energy-inefficient brick kilns. A
significant energy saving can therefore be realised by replacing the current
clamp kiln with a fixed kiln of some kind (e.g. VSBK, Zig-zag, TVA, tunnel kiln,
etc.). The choice of kiln is subjective and dependant on many factors such as the
projected output, the type of product to be produced (e.g. face bricks or plaster
bricks) and the availability of skilled staff.
Switching to a new kiln type has the potential to drop the energy consumption
from clamp kiln typical values of 4 – 5MJ/kg of fired ware, down to as low as
<1.0MJ/kg of fired ware. Furthermore, not only will the energy performance
improve dramatically, increased yields and reduced waste can also be expected.
A recent successful example is the adoption of VSBK technology in South
Africa which has proven itself to be possibly the most energy-efficient type of
kiln available. Other alternatives which have had recent interest in South Africa
includes the tunnel kiln and the Zig-zag kiln, both of which offer a drying capacity
that the VSBK currently does not.
6.3. Business CasesOne way to assess the opportunities is to classify them in a graph based on their payback period
and ease of implementation, where the size of the opportunity is proportional to the size of the circle.
Based on this rating method and their relevance
for the South African market, 10 best practices
were chosen for detailed business cases. The
choice was confirmed during two workshops
organised in Pretoria and Cape Town, where
participants selected their top opportunities. These
10 opportunities ranked amongst the favourite
ones (details on the workshops are provided in the
appendices).
1. Replace the current clamp kiln with a fixed kiln
(e.g. VSBK, Tunnel Kiln)
2. Addition of waste products (e.g. sewerage
sludge, paper pulp)
3. Controlled and efficient combustion of fuel
4. Use of recent model mobile plant and
movement optimisation
5. Increase perforation size of extruded bricks
6. Reduction of the thermal mass of kiln car
decks using lightweight refractory or fibre
7. Waste heat recovery
8. Variable speed/frequency drives
9. Energy management
10. Optimisation of air compressors
Figure 22: Classification of a subset of opportunities according to their payback period and ease of implementation
6.3.1. Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln, etc.)
A typical South African clamp kiln
Tunnel kiln alternative
VSBK Alternative
Heat exchanger
Energymanagement
Upgradingburner controls
Structuralheat loss
VSD on air movementfans
Ease of Implementation
Pay
back
more difficult
long
er
Reducing m/cbrick/coal
Improvingraw materialconsistency
Waste productsas fuels
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201650 51
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln)
Technology
maturity and
need for
support
Approximately 60% of South Africa’s brick production is sourced from clamp
operators. Many of these are family-owned businesses which have been
producing bricks in clamp kiln for up to three generations. Hence, their current
operational methodology is entrenched.
Notwithstanding the above, tunnel kilns have been operating in South Africa
since the 1960s. Transverse arch kilns have a similarly lengthy history and
recently, VSBKs have gained traction. A type of Zig-Zag kiln also operated
continuously for almost 30 years, although widespread adoption of this style of
kiln has yet to occur.
Traditionally, tunnel kiln technology was the reserve of European suppliers
such as Keller, Lingl, Direxa (Ceric) and Hässler. Lesser known or now defunct
marques such as Walter and Dillers Kilns amongst others, also built tunnel kilns
in South Africa but recently, Chinese technology has made some inroads into
the South African tunnel kiln market. Should tunnel kiln technology be chosen,
there are certainly a number of capable suppliers available depending on the
customer’s requirements.
VSBK is supported in South Africa by a local entrepreneur who has gained
considerable experience with the technology over a short period. Initial uptake
was sluggish, but recently, a number of new VSBK projects have broken ground.
Each new project is a learning experience with this technology in South Africa
and as uptake grows, further improvements are anticipated which will benefit
future customers. Conversely, as the technology becomes more popular and
improves, future customers are likely to pay more than the early adopters.
Recently, Habla Zig-Zag Kilns International (HZZKI) commenced building a
proprietary Zig-Zag kiln in South Africa. Although other Zig-Zag kilns have been
built in the past, Habla Zig-Zag claim their kiln design to be superior. A Russian
company, Stromtechnica, also visited South Africa recently. Although their kiln
design - an intermittent chamber kiln with removable roofs - appears promising,
the company has yet to gain traction in South Africa. Notwithstanding, it is likely
that there will soon be other proven alternative technologies to clamp kilns
available for the consideration of South African brick manufacturers.
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln)
Possible
project
approach
The first step towards an alternative kiln technology is recognising the need for change.
Although clamp kiln methodology may have been entrenched over generations,
change agents such as carbon taxes, rising fuel costs and environmental charges are
likely to enforce change. The labour landscape in South Africa is also changing and it
is unlikely that clamp kiln operation will remain sustainable in South Africa.
The projected output, type of product, the availability of skilled staff and the need
for mechanised drying are important factors to consider in choosing an applicable
technology. Furthermore, clamp kiln operators will already have a milling and extrusion
operation in place – there is no benefit in installing a high technology kiln when the
rest of the plant is not up to a similar level. Upgrading dematerialisation and extrusion
may also be necessary.
Current thinking suggests that tunnel kilns are best suited to high outputs and the
highest quality of product. Tunnel kilns also generally provide hot air for drying, however
tunnel kiln technology is likely to work out the most expensive, both from a capital and
operational cost perspective.
VSBK technology has proven effective for a regional manufacturer. Although the
technology is scalable, each VSBK shaft requires operator care on a 24/7 basis, which
is a concern for higher volume producers. Additionally, the manual handling and kiln
environment of VSBKs pose limitations to the level of product that a VSBK can produce.
However, these limitations are not insurmountable and the cost of VSBK technology is
certainly attractive. Currently, VSBK technology does not offer mechanised drying - a
drawback in areas with significant seasonal weather patterns.
In most cases, construction of a fixed kiln will require external support. A variety of
suppliers is available if the manufacturer is clear on his/her technology choice, but in
the face of bewildering technology choices, the CBA (or some of its members) and the
EECB may also provide guidance.
Once a technology choice has been made, it is useful to obtain quotations from more
than one potential supplier. Each supplier will bring their own solution, allowing the
manufacturer to consider which may be best suited to their operation. Once the
solution is chosen, various service providers such as project managers, engineers
and contractors will usually be needed to take the project to fruition as many brick
manufacturers do not have all the in-house expertise required. Often, it is beneficial
for a manufacturer to focus on maintaining the health of the existing business while
the kiln technology upgrade proceeds rather than focussing entirely on the project
at the expense of the regular business. Resources such as the CBA and EECB may
be able to provide suggestions as to experienced service providers who can assist
manufacturers.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201652 53
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln)
Estimated
project cost
Cost to deploy: Varies
All technology types will require regulatory approval of some kind. Depending
on the site and the complexity involved, an environmental impact assessment
may add a cost of up to R250,000 to a firing technology upgrade project.
A tunnel kiln with a dryer capable of producing about 30 million bricks per
annum is likely to cost from R30 million upwards, depending on the technology
supplier. Note that this cost represents the lower end of the spectrum. A tunnel
kiln with a dryer and kiln cars could be a lot more expensive.
An 18-shaft VSBK plant capable of producing about 30 million bricks per
annum is likely to cost around R18 million. Note that this figure represents the
lower end of the spectrum.
Projected costs on the Habla Zig-Zag Kiln are currently unknown, and costings
are also not available for other kilns such as the Stromtechnica design. As both
designs are currently aimed at lower outputs, costs will need to be scaled for
comparison against the above.
Time to deploy: Varies
Construction time on a tunnel kiln could be as long as nine months. A VSBK
project or another type of kiln could be similar or less, but in all cases, the time to
deploy will be subject to regulatory approval. A clamp kiln manufacturer starting
from scratch may face a wait of up to a year before the requisite regulatory
approval is received and the project may legally proceed.
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln)
Saving
For the purposes of cost comparison, a VSBK is the fairest direct comparison
against a clamp kiln as neither technology is currently able to dry bricks.
Additionally, tunnel kiln operating costs and fuel consumption can vary quite
widely depending on the products made. Hence, the focus of this section is the
VSBK.
If a clamp yard producing 30 million bricks per annum is upgraded to VSBKs of
a similar output, the specific energy consumption of the kiln is likely to drop from
around 11GJ/1000 BE to about 2.6GJ/1000 BE. Please note that the energy
consumption of clamp kilns varies quite widely – some clamp kilns consume
significantly more energy than 11GJ/1000 BE. Additionally, it is assumed that
the adoption of VSBK technology will include the adoption of perforated bricks
– a fired weight decrease from 3.1kg to 2.6kg per brick has been included in
the calculations.
30 million bricks per annum @ 11GJ/1000 BE = 330,000GJ per annum
30 million bricks per annum @ 2.6GJ/1000 BE = 78,000GJ per annum
Energy saving is 330,000 – 78,000 = 252,000GJ per annum
The CO2 saving potential is 24,700 / t CO2per annum.
Coal, the most common kiln fuel source, is generally more expensive in coastal
regions than inland. Assuming a fuel cost at the coast of R1,310/t and R800/t
inland, annual cost savings are estimated at:
Coastal – R12.7 million
Inland – R7.75 million
Payback
Following the above example of replacing clamp kilns producing 30 million
bricks per annum with VSBKs of a similar output, a capital spend of approxi-
mately R18 million is required. On fuel savings alone (improvements in yield and
waste are also anticipated), simple payback can be calculated as:
Coastal – 1.4 years
Inland – 2.3 years
Site Energy/CO2
saving per site
Site energy saving:252,000GJ per annum
Site CO2 saving: 24,700t CO2per annum
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201654 55
Replace the current clamp kiln with a fixed kiln (e.g. VSBK, Tunnel Kiln)
Sector Enegy/
CO2 saving
potential
Currently, 60 – 70% of brick manufacturing plants in South Africa use clamp
technology. The cumulative output of all the clamp kilns in South Africa varies
significantly according to demand but it can be reasonably assumed that a
minimum of 1 billion bricks are produced annually in South African clamp kilns.
50% shift to VSBK technology
Sector energy saving: 4,200,000GJ per annum
Sector CO2 saving: 412,000t CO2 per annum
100% shift to VSBK technology
Sector energy saving: 8,400,000GJ per annum
Sector CO2 saving:824,000t CO2 per annum
It is unlikely that all clamp producers will shift towards VSBK technology –
scalability issues and the lack of a mechanised drying options are the chief
concerns. Other kiln technologies will also replace clamp kilns but significantly,
if international trends are mirrored in South Africa, it is likely that output from
brick producers who do not move forward and change will eventually be lost to
alternative building products.
Market
penetration
The South African brick industry has a history of resisting change. Should a
climate conducive to change be created by the correct blend of incentives and
punitive measures, major change is possible within 20 years.
Barriers to
adoption
i. Business confidence (concerns about consistency and volatility)
ii. Cost and availability of finance
iii. Entrenched operational methodology
iv. Relatively low fuel costs in inland areas
v. Concerns on scalability of kiln technology
vi. Lax environmental legislation
Risks to clamp
kilns
i. Increasing environmental compliance / legislation requirements
ii. Carbon tax
iii. Market volatility
iv. Labour volatility
v. Alternative building materials
Addition of waste products (e.g. sewerage sludge, paper pulp)
Development
Description
The addition of waste products (e.g. sludge from a sewerage treatment work,
paper pulp etc.) can offer a multitude of benefits to clay brick manufacturers.
Often, these benefits can be obtained at low rates or in some cases, brick
manufacturers can receive waste streams for nothing or even be paid to accept
them. Depending on the nature of the waste product, potential benefits include:
• Dematerialisation, i.e. lower raw material usage
• Reduction in requirement for process water (many wastes contain significant
amounts of water)
• Improvement in workability / extrudability of the column, thus requiring
lower energy for the extrusion process and sometimes obviating the need
for additional die lubrication
• Fuelling benefits
• Production of lighter bricks
Clearly, various waste products can have wide-ranging positive effects for brick
manufacturers and for this reason, it is difficult to cover them all.
Waste addition can
replace up to 15% of
regular raw materials
Extruder Amps can be
lowered and die lube can
be changed to water or
even turned off
Depending on the waste,
fuel swaps of up to
100% of the regular fuel
are known
Lighter bricks reduces
transport costs and can
significantly enlarge a
factory’s footprint
6.3.2. Addition of Waste Products (e.g. sewerage sludge, paper pulp)
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201656 57
Addition of waste products (e.g. sewerage sludge, paper pulp)
Technology
maturity and
need for support
The use of waste products is not widespread in South Africa. This is probably
due mostly to the lack of useful waste products or possibly the communication
gap between producers of such waste products and brick manufacturers. On a
secondary level, there may be some legislative or technical hurdles to overcome
which dissuade brick manufacturers from considering waste streams. The
recent introduction of the requirement for a waste licence is a significant hurdle
for brick manufacturers who are using / want to use waste products in their
processes.
Notwithstanding the above hurdles, the requirement for new technology
is generally limited - meaning that minimal specialist support is needed. In
most cases, only basic infrastructure such as box feeders and, or bundled
storage areas are required making this opportunity accessible to most brick
manufacturers. The proviso is that a suitable waste product stream needs to be
available. Although waste product streams seem to have better availability in the
vicinity of metropolitan areas, regional producers close to agricultural or mineral
processing facilities may also have access to useful waste streams.
Possible project
approach
The CBA (or some of its members) and the EECB may provide some guidance
to brick manufacturers who wish to consider using waste streams. Government
initiatives are also useful resources – the Western Cape has a programme
known as the Western Cape Industrial Symbiosis Programme (WISP), which
specifically aims to assist its members, especially SMEs, fill gaps in experience
or provide additional resourcing towards identifying and implementing resource,
waste and energy efficient practices.
On a practical level, significant trials can be done in laboratories and test
kilns before factory trials need proceed. In this regard, there are a number of
professional service providers in South Africa and abroad who are able to assist
brick manufacturers and provide external technical expertise.
Should a case prove promising, manufacturers require a waste licence to
commence brick production using a waste product stream as an additive. In
most cases, a full environmental impact assessment (EIA) is required in order
to obtain a waste licence – it is necessary that this be carried out by external,
independent professionals. Factors surrounding the site, the process and the
waste stream can influence the programme and cost significantly but a full year
from start to finish is about normal.
Addition of waste products (e.g. sewerage sludge, paper pulp)
Estimated
project cost
Cost to deploy: R 500,000
Approximately R200,000 of the above amount may be required for the EIA. The
remainder is the estimated amount required for a straightforward box feeder
and delivery conveyor belt.
Time to deploy: 1 year
Saving
Due to the wide-ranging possibilities out there, it is not possible to cover all
potential waste streams. This analysis will therefore focus on one particular
waste stream– the usage of sludge from a waste water treatment works.
Assumptions:
30 million bricks produced per annum
Raw material cost R40/1000BE
8% of raw material by volume replaced by sludge
Sludge calorific value of 16MJ/kg
Sludge water content of approximately 70%
Average drop in extruder current 15A for 9.5hrs per day
Firing energy requirement 5.0GJ/1000BE
Fuel cost approximately R4.00/kg for fuel with 43MJ/kg energy content
Electricity cost R0.72/kWh
Energy saving calculated from drop in extrusion current only
Cost saving calculated from reduction in fuel cost and minor electricity saving
Savings
Energy saving:103,000 MJ per annum
Cost saving: R2 Million per annum
The CO2 saving potential is 27t per annum (at 0.94kg CO2 per kWh electricity
in SA)
Payback
Based on the sludge example above, payback can be calculated as follows:
1 year, 3 months (assuming EIA takes 1 year to complete)
Site Energy/CO2
saving per site
Site energy saving: 103,000 MJ per annum
Site CO2 saving: 27tCO2 per annum
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201658 59
Controlled and efficient combustion of fuel
Development
Description
Energy savings can be achieved through the optimisation of the temperature
profile in the kiln and the effective utilisation of firing fuel. Best practice demands
a steady rise in temperature through clean and efficient combustion of fuel
and for this reason, automated fuelling through proprietary burner systems
is preferable to manual fuel feeding. Even when basic automation is already
installed, more advanced firing control through programmable logic controllers
(PLCs) and proportional integral derivative (PID) controllers can still achieve
significant gains in efficiency.
Additional benefits anticipated include improved yield and reduced waste. A
burner system that is erratic or inconsistent may over-fire and clinker in some
places, while leaving other areas under-burnt.
Addition of waste products (e.g. sewerage sludge, paper pulp)
Sector Energy/
CO2 saving
potential
Replicability across the sector is limited by the availability of waste streams.
Assuming that 70 of the approximately 90 CBA manufacturing sites may be
suitable for the use of waste streams, an upper figure of 20 sites is estimated as
having the potential to use waste streams in brick manufacturing. Furthermore,
each waste stream may have different energy saving characteristics, so
assumptions made across the sector should be viewed with this understanding.
Sector energy saving: 2,060GJ per annum
Sector CO2 saving: 540t CO2 per annum
Market
penetration
If all 20 potential sites begin the process of identifying and testing various waste
products immediately, a period of three – five years is estimated for uptake of
this opportunity. Following any initial uptake, new developments will continually
create additional opportunities from time to time.
Barriers to
adoption
i. Availability of waste products near the plant
ii. Environmental compliance / legislation
iii. Security of tenure over the waste stream
iv. Cost of the additional infrastructure needed
v. Clamp yards may struggle when waste stream is inconsistent
vi. Technical difficulties
Risks
i. Some waste products can degrade the bricks produced
ii. Increasing environmental compliance / legislation requirements
iii. Clamp yards have long lead times and require significant investment in
work in progress – this discourages trials
iv. Some wastes may produce dangerous by-products
v. Dangers to staff with manual handling
6.3.3. Controlled and Efficient Combustion of Fuel
Tunnel kiln heavy furnace
oil burner installation –
burners are simple and
inefficient and control
very broad
Chain-driven coal duff
feeders that replaced
manual feeding
Temperature PID
controller – as long as
the green number <
the red number, fuel is
added
Computerised tunnel kiln
firing control system
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201660 61
Controlled and efficient combustion of fuel
Technology
maturity and
need for support
Existing installations in South Africa range from those with manual fuel addition
through to high-tech automated systems. Although best practice installations
are usually proprietary systems from experienced European suppliers such as
Keller, Lingl, Direxa (Ceric), Beralmar, High-Tech etc., locally sourced equipment
can also present a significant step-up from manual feeding.
With regard to local sourcing, the CBA (or some of its members) and the
EECB may provide some guidance to brick manufacturers wishing to upgrade
their systems. In addition, there are numerous South African mechanical and
electrical contractors capable of providing significant support in this arena.
Possible project
approach
The level of investment and modifications required on the kiln is highly
dependent on the kiln and existing automation. A kiln in the open with minimal
electrical installation may necessitate more work and investment than a kiln
that is already under a roof. Conversely, a tunnel kiln already fitted with a basic
automatic firing system may require a significant investment to upgrade the
system to the next level.
In many cases, internal expertise should recognise the need for the investment.
However, the finer details of the proposed project are best worked out with
external service providers such as proprietary firing system suppliers or
mechanical and electrical contractors.
Estimated
project cost
Cost to deploy: R 250,000 – R1,000,000 (varies according to existing
level of automation)
Time to deploy: 3 – 9 months (varies according to existing level of
automation)
Saving
Potential savings are dependent on the type of fuel used and the initial level of
kiln efficiency. The type of fuel used is further dependent on the location of the
plant – if coal is the fuel source, coastal areas generally pay more than inland
areas. For calculation purposes, controlled and efficient combustion is estimat-
ed to improve fuel consumption by an average of 5%. The anticipated additional
benefits of improved yields and reduced waste are omitted from the calculation.
Coal firing
Assumptions:
30 million bricks produced per annum
Main firing fuel is B grade nuts with energy content 26MJ/kg
Coastal energy cost: R1,460/t
Inland energy cost: R950/t
Initial firing energy requirement 8.0GJ/1000BE
5% Energy saving due to controlled and efficient combustion
Controlled and efficient combustion of fuel
Saving
continued
Savings:
Energy saving of 12,000GJ per annum
Coastal – R670,000 per annum
Inland – R440,000 per annum
HFO firing
Assumptions:
30 million bricks produced per annum
Main firing fuel is HFO with energy content 43MJ/kg
HFO cost R4/kg
Initial firing energy requirement 5GJ/1000BE
5% Energy saving due to controlled and efficient combustion
Savings
Energy saving: 7,500GJ per annum
Cost saving: R700,000 per annum
Payback
A range is provided due to the potential range of project costs.
Project cost R250,000
Coal firing
Coastal – 4 months
Inland – 7 months
Project cost R1 Million
Coal firing
Coastal – 1.5 years
Inland – 2.3 years
HFO firing – 1.4 years
Site Energy/CO2
saving per site
Site energy saving: 7,500 – 12,000GJ per annum
Site CO2 saving for coal: 735 to 1,180t CO2 per annum
Site CO2 saving for HFO: 540 to 860t CO2 per annum
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201662 63
Controlled and efficient combustion of fuel
Sector Energy/
CO2 saving
potential
Replicability across the sector is limited to the number of fixed kilns in South
Africa currently estimated at 30% of the sites or about 25 plants. Of these sites,
it is anticipated that about 10 sites may not benefit greatly from investment into
controlled and efficient combustion suggesting that 15 sites may have potential
for this energy saving opportunity. As each site has a different output capacity,
the lower value of 7,500GJ per annum is applied to 15 sites.
Sector energy saving: 112,500GJ per annum
Sector CO2 saving: 11,000t CO2 per annum (coal)
Market
penetration
The potential for energy saving at the above mentioned 15 sites is real as are
the potential cost savings and payback. Nevertheless, a combination of factors
(see barriers to adoption) have tended to minimise investment in this area.
Should business confidence improve and a climate conducive to change be
created by the correct blend of incentives and punitive measures, it is estimated
that five of the 15 sites may upgrade firing systems within five years with a
further four sites upgrading within 10 years.
Following any initial uptake, new developments will create additional
opportunities from time to time.
Barriers to
adoption
i. Business confidence (concerns about consistency and volatility)
ii. Cost and availability of finance
iii. Relatively low fuel costs in inland areas
iv. Doubts over potential improvement
v. Entrenched operational methodology
vi. Lax environmental legislation
vii. Technical difficulties
Risks
i. Continued availability of same fuel
ii. Increasing environmental compliance / legislation requirements
iii. Carbon tax
iv. Market volatility
v. Labour volatility
vi. Alternative building materials
6.3.4. Use of Recent Model Mobile Plant and Movement Optimisation to Reduce Energy Use
Use of recent model mobile plant and movement optimisation to reduce energy use
Development
Description
When it comes to replacing or maintaining mobile plant, brick manufacturers
face a difficult decision. Is it better to maintain old machinery that is possibly
owned outright, or replace it with new plant that may need to be financed?
From an energy efficiency point of view, current generation mobile plant can
use as little as 50% of the fuel needed by older generation plant. Additionally,
the capacity of plant has improved to such a degree that a new machine with
a similar footprint to an old machine is now capable of doing almost twice the
duty. For example, a new 5t rough terrain forklift can fulfil the duty of two old
generation rough terrain forklifts, each with a lifting capacity of around 3t.
As a general rule, most new generation mobile plants are supplied with an
enclosed cab which not only provides all-weather operator comfort but also
significantly improves operator and pedestrian safety. In some cases, a single
machine can fulfil the duty of two older machines, meaning that the second plant
operator can be redeployed. New generation machinery is generally quieter and
hence, reduces the need for hearing protection when operated inside.
Lastly, it is likely that the best return in a brick manufacturing operation is
achieved when the manufacturer is able to concentrate on making bricks.
Notwithstanding the downtime potential, the maintenance of older mobile plant
can demand significant attention, and time that can be more fruitfully spent
elsewhere. The shortage of good artisans - such as diesel mechanics -in some
areas exacerbates this
Newer generation forklifts
with enclosed cabs and
multiple tines
Older forklift with open
seating and 2 tines
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201664 65
Use of recent model mobile plant and movement optimisation to reduce energy use
Technology
maturity and
need for support
The use of newer mobile plant is quite varied across South African brick
manufacturers. At some larger plants, one may see a fleet of as many as 23
recent model forklifts, whereas similar operations nearby maintain their fleet of
older machines. Similar contrasts can be seen with front-end loaders and other
earth moving machinery – front-end loaders from the 1980s are not uncommon.
For those manufacturers considering new plant, there are numerous mobile
plant brands active in the brick manufacturing arena, represented by a number
of different companies. In no particular order, these brands include Manitou,
Volvo, Bell, Linde, Cat and Komatsu, amongst numerous others. Some brands
are stronger in particular areas or particular types of equipment and brick
manufacturers are encouraged to shop around for a solution tailored to their
needs.
Possible project
approach
Recognising the need to update mobile plant is never easy. While new
machinery is less likely to experience serous issues than old equipment, older
machinery that is adequately maintained is not always in need of renewal. The
establishment of clear cut policies with regards to mobile plant renewal is
therefore not straightforward and involves site-specific consideration, including
the required duty and the potential costs of an unexpected failure. The availability
of good artisans is another important consideration.
Establishing the real cost of maintaining old equipment is a useful step. Although
funds spent on parts and service providers are easy to track, management and
staff time spent on machinery maintenance is much harder to account for.
With an effective management system functioning, mobile plant suppliers, the
CBA (or some of its members / associates) and the EECB may provide some
ideas to brick manufacturers considering plant renewal. External ideas may be
useful as brick manufacturers who are used to doing things in a certain way
may not be aware that there are other, more cost effective ways of achieving
the same result. In some cases, movement studies can be useful towards
determining whether there is scope to replace two or more smaller capacity
machines with fewer, larger capacity plant.
Estimated
project cost
Cost to deploy: Varies
Examples:
• 5t rough terrain forklift: R920,000 or hire purchase for R22,000 per month
over 60 months – dealer maintenance costs R12,612 per month dependent
on duty
• Front-end loader with standard 2.3m3 bucket and 95kN breakout force:
R1,68 Million – dealer maintenance costs around R23/hr dependent on duty
Time to deploy: From immediately to a few months
Use of recent model mobile plant and movement optimisation to reduce energy use
Saving
Due to the wide-ranging possibilities out there, it is not possible to cover all
potential uses of mobile plant in the brick manufacturing sector. Hence, this
analysis will focus on an actual case where a brick manufacturer chose to
replace two older model rough terrain forklifts with a single, larger capacity
machine.
Assumptions:
Old machines (owned outright)
Approximate value: R150,000
Holding cost of capital: 10%
Annual ownership costs: R15,000
Monthly maintenance costs: R5,000
Capacity: ±3t (i.e. enough for 1 pallet of green bricks)
Monthly operating hours: 400
Diesel usage: 6l/hr
Litres of diesel per month: 2,400l
Driver costs: R7,500 per month or R90,000 per annum
New machines (bought on hire purchase)
Monthly payment: R22,000
Annual ownership costs: R264,000
Monthly maintenance costs: R10,000
Capacity: 5t (i.e. enough for 2 pallets of green bricks)
Monthly operating hours: 400
Diesel usage: 3.5l/hr
Litres of diesel per month: 1,400l
Driver costs: R7,500 per month or R90,000 per annum
Diesel price: R11/l
2 x old machines replaced by 1 x new machine
Energy saving of 1,530GJ per annum (annual diesel saving of 40,800/l)
Cost saving
(40,800l x R11/l)+(R30,000 – R264,000)+R90,000 = R304,800 per annum
Note on cost saving: For the purposes of simplicity, depreciation and tax have been omitted. A capital incentive tax allowance of 40% of the value of the new equipment can be used to reduce company tax payable in the first year and defer tax thereafter. Hence, a company’s financial structure and profitability may act towards enhancing the cost saving given above. Brick manufacturers are encouraged to obtain professional accounting advice in this regard.
The CO2 saving potential is 110t per annum.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201666 67
Use of recent model mobile plant and movement optimisation to reduce energy use
Payback Immediate in above example, but will vary
Site Energy/CO2
saving per site
Site energy saving will vary depending on machinery and replicability.
Assuming above operation replaces four old forklifts with two newer machines,
site energy saving is 3,060 GJ per annum.
Site CO2 saving will vary depending on machinery and replicability
Assuming above operation replaces four old forklifts with two newer machines,
site CO2 saving potential is 220 t per annum.
Sector Energy/
CO2 saving
potential
The forklift example above is an ideal combination of hours, terrain and duty,
used to illustrate the point. Not every site will offer savings potential at this
level and in many cases, significant energy savings may not be accompanied
by significant cost savings, thereby limiting the uptake. On this basis, it is
assumed that 50% of brick manufacturing sites (around 43 sites) may offer
energy saving opportunities of 50% of the level illustrated in the above example
(1,500GJ per annum).
Sector energy saving: 64,500GJ per annum
Sector CO2 saving: 4,600t per annum
Market
penetration
Company policies regarding mobile plant renewal will always differ. Different
attitudes towards risk, levels of business confidence and the availability of
skilled artisans will see some firms updating their plant regularly, while others
choose to maintain what they already have. A further complication is that mobile
plant is improving all the time and the best performance in 2015 may only be
average in a few years’ time.
Based on the above, it is suggested that 50% of brick manufacturers may work
towards a mobile plant renewal system or policy within five years. During the
same period, approximately half may act on their policy towards evaluating their
mobile plant duties and consider mobile plant renewal. The remainder are likely
to continue mobile plant renewal on an ad hoc basis.
Barriers to
adoption
• Business confidence (concerns about consistency and volatility)
• Cost and availability of finance
• Complex tax laws
• Lack of mobile plant management systems and policies
• Entrenched existing operational methodology
• Doubts over potential improvement
• Lax environmental legislation
Risks
• Availability of skilled artisans
• Emergence of new generation, more efficient mobile plant
• Business volatility
• Labour volatility
• Government legislation and changes in tax law
6.3.5. Increase Perforation Size of Extruded Bricks
Increase perforation size of extruded bricks
Development
Description
As long as the percentage of perforations in a brick is below 25%, the brick
is deemed to be a solid masonry product. The potential to use 25% less raw
material - with commensurate savings in energy - is appealing. Nonetheless, it
is estimated that more than 60% of South Africa’s clay bricks are made without
any perforations.
In the clay brick manufacturing process, perforated bricks use less raw material,
meaning mine life is extended and raw material costs are reduced. As less raw
material is needed, less energy is also consumed in clay preparation and there is
less wear on the machinery for the same brick output. In the extrusion process,
the reduced volume through the extruder for perforated products is balanced
by the higher extrusion pressures that may be needed for perforated products.
Due to the reduced volume, forming and shaping requires less water and
commensurately, less heat and air flow are required for drying. If setting density
is maintained in the kiln, a greater volume of bricks can be fired in the same kiln
using less energy per brick than bricks made without perforations. Outside the
factory building, any manual handling is improved due to the reduced weight of
perforated products and mobile plant such as forklifts and trucks are also able
to handle more of the product at a time with reduced energy consumption per
brick.
In clamp yards specifically, perforated products dried in the open may dry faster.
Clamp kilns may also fire faster due to the reduced mass, thereby improving the
cycle time, reducing work in progress and saving cost. The additional circulation
in clamp kilns provided by perforations has also been known to improve product
consistency.
The energy and cost implications of the above are clear. Less obvious is the shift
in building trends towards products regarded as “greener” and more sustainable.
If international trends are mirrored in South Africa, brick producers who choose
to manufacture non-perforated products will eventually find themselves on the
losing side of these trends, with part of the market share moving to alternative
building materials.
Solid bricks Perforated bricks
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201668 69
Increase perforation size of extruded bricks
Technology
maturity and
need for support
It is estimated that >30% of the bricks manufactured in South Africa are
perforated. Hence, there is much experience to draw from, and manufacturers
have a multitude of sources from which advice can be sought.
Brick Management and Manufacturing Supplies (BMMS) are the South African
agents for JC Steele and Händle and are therefore well-versed in the equipment
needed for perforated extrusion. South Africa is predominantly a stiff extrusion
market and while there are other companies that manufacture dies specifically
for stiff extrusion, Reymond Dies, a stiff extrusion die specialist, is possibly the
best known alternative.
In the semi-stiff extrusion space, a number of European suppliers can provide
support. Braun, a well-known German die manufacturer has recently come
under the Händle umbrella. Other brands active in this area include - amongst
others - Bongiani Stampi and Tecnofiliere, who provide brick manufacturers
with a number of avenues to follow for support.
Possible
project
approach
The first step towards perforated extrusion is recognising the need for
change. Although solid extrusion methodology may have been entrenched
over generations, change agents such as carbon taxes, rising fuel costs and
environmental charges are eventually likely to enforce a shift. Where manual
handling is involved, the difference in weight between solid and perforated
bricks may also drive the change process. A handful of clamp kiln manufacturers
have already made the change successfully.
If a manufacturer has generally only made solid bricks, it is likely that some
external advice on the finer points of perforated extrusion may be needed.
In many cases, a grinding regime that is sufficient for solid bricks may prove
inadequate for perforated extrusion, thereby requiring significant effort before
the extruder. Local suppliers may be able to advise manufacturers or alternatively,
the CBA (or some of its members) and the EECB may provide guidance.
In most cases, a step by step approach is advocated, whereby small scale trials
are conducted and evaluated. An imbalanced die leading to invisible drying
cracking may make it appear as if perforated bricks do not fire effectively in a
clamp kiln, whereas the real problem may lie elsewhere. If green strength is an
issue, manual handling may exacerbate issues.
Increase perforation size of extruded bricks
Estimated
project cost
Cost to deploy:
Starting from R40,000, but could vary greatly
(Cost can reach R500,000 per extruder)
Should a manufacturer already have a suitable crushing regime, the initial outlay
could be limited to a die base capable of anchoring a bridge, along with said
bridge, cores and possibly a shaper cap. Manufacturers wanting to trial such a
system may be able to borrow this equipment at minimal expense.
Should the existing crushing system be insufficient, additional machinery may
be needed to obtain the required throughput at the correct raw material particle
size, to shift from solid to perforated brick extrusion. This could have significant
cost implications.
Time to deploy: 1 year, but could vary
It is suggested that small scale trials be carried out over time. Due to the time
taken for open air drying and clamp firing, initial trials could take more than three
months and prove unsuccessful. Similarly, seasonal variations could introduce
other variables that require time to resolve. If there are brick plants in South
Africa with mechanised drying and fixed kilns that are not producing perforated
product, the time to deploy could be greatly shortened.
Saving
The vast majority of solid bricks made in South Africa are produced with clamp
kiln technology. Hence, cost saving calculations are focussed on a clamp yard
nominally producing 30 million bricks per annum, in which perforations of 10%
are introduced (three holes of about 33mm diameter). As it is commonly ex-
pected that the introduction of perforations at a clamp yard results in increased
waste, an additional 3% loss due to waste is included in the calculations.
Coal duff, the most common clamp kiln fuel source, is generally more expensive
in coastal regions than inland. Assuming a fuel cost at the coast of R1,310/t
and R800/t inland, annual cost savings are estimated as follows:
Clamp Firing
Assumptions:
30 million bricks produced per annum
Perforations of 10%
Raw material cost of R40/1000BE
Cost to crush finer balanced by reduced volume required
Initial firing energy requirement 11.0GJ/1000BE (based on solid bricks)
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201670 71
Increase perforation size of extruded bricks
Saving
continued
Firing fuel coal duff
Inland cost: R800/t
Coastal costs: R1,310/t
Average delivery charges: R300/1000BE
10% weight saving translates into a 5% saving on delivery costs
Average brick sales price R1,300/1000BE
Additional waste due to perforations: 3%
Cost to move additional waste balanced by savings in moving lighter product
elsewhere
Energy saving assumed as proportional to perforation percentage
Cost savings calculated from reduction in fuel cost, savings on raw materials and
delivery charges, minus additional losses due to increased wastage
Savings:
Energy saving of 33,000GJ per annum
CO2 saving is 3,230t per annum (at 98kg CO2 per GJ for coal).
Coastal – R1.06 million per annum
Inland – R415,000 per annum
Payback
Assuming the fuel costs used above, the balancing point of the payback
calculation comes down to any additional waste produced. If the amount of
additional waste can be kept at 3% or lower, payback is very quick and would
justify the installation of additional clay preparation machinery if required. Based
on the savings detailed above, simple payback is calculated as follows:
Coastal – 2 weeks
Inland – 1 month
Site Energy/CO2
saving per site
Site energy saving: 33,000GJ per annum
Site CO2 saving: 3,230t CO2 per annum
Increase perforation size of extruded bricks
Sector Energy/
CO2 saving
potential
Currently, 60% – 70% of brick manufacturing plants in South Africa use clamp
technology and only a small percentage of those produce perforated bricks. The
cumulative output of these plants varies significantly according to demand, but it
can be reasonably assumed that a minimum of 1 billion solid bricks are produced
annually in South African.
20% shift to product with10% perforations:
Sector energy saving: 220,000 GJ per annum
Sector CO2 saving: 21,560 t CO2 per annum
100% shift to product with10% perforations:
Sector energy saving: 1,100,000GJ per annum
Sector CO2 saving: 107,800t CO2 per annum
Market
penetration
The South African brick industry has a history of resisting change and there
is considerable resistance to the introduction of perforations. Although almost
all extruded clay brick manufacturers could produce perforated bricks, the
entrenched operational methodology of solid brick manufacturers will be difficult
to change.
Should a climate conducive to change be created by the correct blend of incentives
and punitive measures, it is estimated that a 20% shift towards perforated
products could occur over 10 years. After this time, if international trends are
mirrored in South Africa, it is likely that output from brick producers who do not
move forward and change will eventually be lost to alternative building products.
Barriers to
adoption
i. Entrenched operational methodology
ii. Perception that “the market only wants solid bricks”
iii. Lax environmental legislation
iv. Technical difficulties
v. Relatively low fuel costs in inland areas
Risks
i. Increasing environmental compliance / legislation requirements
ii. Carbon tax
iii. Clamp yards have long lead times and require significant investment in
work in progress – this discourages trials
iv. Labour volatility and willingness to pack solid bricks
v. Market uptake of perforated bricks
vi. Alternative building materials
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201672 73
6.3.6. Reduction of the Thermal Mass of Kiln Car Decks using Lightweight Refractory or Fibre
Reduction of the thermal mass of kiln car decks using lightweight refractory or fibre
Development
Description
Tunnel kiln energy balances show that a considerable amount of heat is lost
through the base of the kiln cars. These losses come about due to conduction
of heat through the kiln car structure and are exacerbated by kiln cars of high
thermal mass. High thermal mass is problematic as it is difficult to recover all
the heat energy from a kiln car of high thermal mass within the kiln. Hot kiln
car decks emerging from the kiln normally cool slowly in the factory building,
thereby wasting the heat held in the kiln car decks.
Due to normal wear and tear, kiln car decks require renewal from time to time.
In most cases, it is simpler for the plant operator to renew kiln car decks using
the existing deck design. Nonetheless, in many cases, a redesign of the decks
could lead to the incorporation of lighter weight materials, which would reduce
thermal mass as well as conduction losses. Redesigned kiln car decks will be
significantly cooler on leaving the kiln, translating into additional energy retained
in the kiln system and a saving on fuel, with a commensurate cost benefit.
In addition, rebuilt kiln cars will also receive new inter-car seals. Over and above
the fuel and cost saving from the lightweight decks, it is well-documented that
inter-car seals of good quality can have a significant positive effect on tunnel
kiln efficiency. Additional benefits in the form of decreased waste and improved
yield are anticipated.
Original solid refractory kiln car deck
Reduction of the thermal mass of kiln car decks using lightweight refractory or fibre
Technology
maturity and
need for
support
South Africa currently has about 17 sites around the country employing tunnel
kilns. Of these sites, about seven employ modern kiln car deck designs with
support coming mostly from traditional European suppliers such as Burton and
Forgestal, amongst others. Should a solution be needed, suppliers are willing
and able to help, albeit at a cost.
The remaining 10 tunnel kiln sites are generally either still maintaining their
original kiln car detail, using homemade solutions or seeking alternatives such
as those from Chinese suppliers. In this regard, local assistance is available
from consultants and refractory suppliers. The CBA (or some of its members
and associates), along with the EECB may provide some guidance to brick
manufacturers wishing to upgrade their kiln cars.
Possible
project
approach
Many tunnel kiln operators lack the internal expertise to do anything else other
than perpetuate their original deck design. In order to change to a lighter weight
design, a consultant or engineering designer is needed to explore a range of
options and ensure that a design is chosen that is fit for the particular duty in
that particular plant – few tunnel kiln plants are exactly alike.
While it would be ideal to build a few cars at a time and evaluate their
performance, this is often difficult as old cars continually damage the newer
cars. At a certain point, it becomes necessary to reconstruct large batches of
cars that can generally run together, leaving only the first and last cars to get
damaged by older cars.
In a typical tunnel kiln plant, there may be 30 kiln cars in the tunnel kiln out of a
total fleet of around 90 cars. Hence, even if 30 cars are refurbished, there will
only be a short space of time when the kiln runs un-influenced by older cars. For
this reason, it will be difficult to measure the overall kiln performance of the new
cars with the refurbishment of a relatively small number of cars. In the short term,
the performance of the design will most likely be evaluated on other aspects,
such as its mechanical robustness.
Estimated
project cost
Cost to deploy: R5.16 Million (at R57,000/car – lower end of the spectrum)
Time to deploy: 2 – 3 years
The cost is dependent on the size and state of the existing kiln cars. Should
significant chassis repairs be required, the cost could be higher - and vice versa.
Similarly, the time to deploy is based on a fleet of approximately 90 cars. If the
plant can afford to refurbish three or four cars per month (from a cost as well as
a process perspective), a complete refurbishment project could be completed
within three years.
New rope seal for
inter-car sealing
Modern kiln
car deck with
large volume
of lightweight
insulation
material
Original solid
refractory
kiln car deck
Old inter-car seal
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201674 75
Reduction of the thermal mass of kiln car decks using lightweight refractory or fibre
Saving
Due to the recovery of process heat that would otherwise be wasted, it is
assumed that reducing the thermal mass of kiln car decks can achieve a 5% fuel
saving. Other benefits, such as improved inter-car sealing and enhanced yields,
have been assumed to provide an additional 5% gain in energy consumption.
Assumptions:
30 million bricks produced per annum
Initial firing energy requirement of 5.0GJ/1000BE
Fuel cost: approximately R4/kg for fuel with 43MJ/kg energy content
Energy saving calculated from reduced firing fuel consumption
Cost saving calculated from reduction in fuel cost
Savings:
Energy saving: 15,000GJ per annum
Cost saving: R1.4 Million per annum
The CO2 saving potential is 1,100 t per annum
Payback 3.7 years
Site Energy/CO2
saving per site
Site energy saving: 15,000GJ per annum
Site CO2 saving: 1,100t per annum
Sector Energy/CO2
saving
potential
Of the 10 tunnel kiln sites that may benefit from reduced thermal mass kiln cars,
50% are unlikely to change their current operational thinking. Hence, replicability
is limited to about five sites of varying outputs. Hence, the estimated saving per
site is reduced to 10,000GJ per annum
Sector energy saving:50,000GJ per annum
Sector CO2 saving:3,700t per annum
Market
penetration
The five sites mentioned above are all likely to undertake kiln car refurbishment
over the next five to 10 years. A climate of high business confidence conducive
to change may speed up the process, but a two to three year project cycle per
site ensures that this opportunity is long term. Hence, a 10-year estimate is
suggested for the five sites mentioned above.
Following initial uptake, new developments will create additional opportunities
from time to time. Additionally, kiln car refurbishment is an ongoing item, but
once lightweight deck design is embraced, the potential for energy reduction
wanes significantly.
Reduction of the thermal mass of kiln car decks using lightweight refractory or fibre
Barriers to
adoption
viii. Business confidence (concerns about consistency and volatility)
ix. Cost and availability of finance
x. Confidence in the mechanical robustness of old designs
xi. Concerns over the mechanical robustness of light weight designs
xii. Doubts over potential improvement
Risks
vii. Damage from old cars
viii. Compatibility with existing cars
ix. Mechanical robustness
x. Cheaper refractory material from China may not match European quality
xi. Labour volatility
xii. Government legislation
6.3.7. Waste Heat Recovery
Waste Heat Recovery
Description
All kilns have exhausts through which the products of combustion and other
emissions are emitted to the atmosphere. These gases are hot and can carry
away a large amount of useful heat - in some cases as much as 1MJ/kg. If
some of this heat could be cost effectively recovered, it could be used as a
virtually free source of heat.
Kilns, tunnel kilns in particular, may also have other sources of waste heat that
can be recovered. These include vented hot air from under car or roof cooling
systems.
There are two ways to recover the waste heat from exhausts:
i) Use it directly as a source of heat
This is possible when the contamination of the exhaust gases is low. This is
a best practice with an excellent return on investment, as the implementation
costs are low and all the heat can be recovered. Examples:
1. Transfer of hot cooling air from the tunnel kiln cooling zone to the dryers;
2. The use of hot cooling air from the tunnel kiln cooling zone as preheated
combustion air;
3. The use of hot cooling air from undercar cooling or roof cooling system as
preheated combustion air.
The use of clean hot air from the kiln’s cooling zone for drying is widespread
for tunnel kilns and an increasing number of kilns are being built or modified so
that lower temperature clean cooling air is used as preheated combustion air.
Paybacks are almost always less than two years.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201676 77
Waste Heat Recovery
Description
continued
ii) Use a heat exchanger to recover heat from exhausts
Heat exchangers are required when the exhaust gases cannot be used directly;
almost all kiln exhausts fall into this category. Initial costs can be high for a
heat exchanger but the resulting “free” heat stream can be used for a variety of
purposes. Examples include:
1. Preheating combustion air;
2. Heating water;
3. Preheating heavy fuel oil prior to firing.
Unfortunately due to their longer payback of three to five years, there are few
examples of flue gas heat exchangers in the brick industry. But as fuel savings
from other sources become increasingly difficult to find, heat exchangers will
become the major source of energy savings for the brick manufacturing business.
Technology
Maturity
Heat exchanger design and technology is fully mature in sectors such as food,
brewing and petro-chemical. Costs for the technology have decreased due to
low steel prices and an increase in demand for mass produced products over
bespoke designs. However, there is little expertise within the brick sector and
its supply chain and the technology within the brick sector can therefore be
considered to be at a very early stage in its maturity.
Project
Approach
All kilns have the potential for heat recovery, but not all will be technically possible
or economically sensible. The following simplified steps will guide companies in
assessing their potential for heat recovery before investing in a full engineering
study.
Shell and tube flue
gas heat exchanger
Waste Heat Recovery
Project
Approach
continued
1. Produce a heat balance for the kiln using a simple heat balance tool.
2. Identify the waste heat sources and whether the hot exhaust can be used
directly or will need a heat exchanger.
3. If the hot air can be used directly, obtain quotations for ducting the hot
air to the burners and for any adjustment to the combustion system to
accommodate the increase in the temperature. Use the heat balance tool to
calculate the saving by using this waste heat as preheated combustion air.
4. If a heat exchanger is required, the flue gas temperature should be above
150oC. Again, use the model to measure the value of the waste heat, but this
time assume only part of it can be recovered using the formula:
where T is the temperature of the exhaust.
Obtain quotations for an installed heat exchanger and ductwork to the burner
system and assess the business case thoroughly. The flue gases should be
analysed for particulate and acid gas composition so that the correct grade
of material can be used for the heat exchanger.
Estimated
Project Cost
Vented Hot Clean Air:
Costs will be low with these types of projects, as they usually simply involve
the connection of a waste heat source with the burner combustion air system;
businesses can often complete the engineering work themselves. Ductwork
should be made of a suitable material and be insulated. The burner combustion
air control system will need to be adjusted to take into account a higher volume
of higher temperature air. In some cases, with very hot combustion air, burner
pipework may need replacing.
Project costs are variable depending on temperature, distances and burners
deployed but a project cost of R200,000 to R1 million is typical. No or little extra
maintenance cost is incurred. These projects can be implemented quickly with
little interruption to the manufacturing process.
Heat Exchanger
Project costs for heat exchangers are much higher. They require:
• Modifications to ductwork and burners or the oil delivery system;
• The purchase of a heat exchanger and the breaking into an exhaust stack.
Typical costs vary between R2 million and 10 million and there will be a small
increase in maintenance costs from inspecting and cleaning the heat exchanger.
= value of waste heat *( T – 120)
T recovered heat value
Tunnel kiln fired with
preheated combustion
air from cooling zone
saving 50kJ/kg
Courtesy of Lingl
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201678 79
Waste Heat Recovery
Estimated
Project Cost
The presence of a heat exchanger in the stack will increase the pressure in
the system and a small increase in power consumption for the exhaust fan will
occur.
These projects take six months to one year to develop and require a shutdown
to be installed.
Saving &
Payback
Based upon an HFO kiln producing 30 million bricks per annum, with an energy
consumption at 5GJ/000, 150,000GJ/year.
Vented Hot Clean Air
Assuming the kiln has a supply of 3,000 kg/hr of vented cooling air at 100oC,
this represents 2,000GJ/year of heat that can be recovered as preheated
combustion air.
Saving: R0.2 million
Estimated Project Cost: R500,000
Payback: 2.5 years
Heat Exchanger
Assuming the kiln has an exhaust temperature of 200oC, approximately
30,000GJ/year of heat is emitted through the stack, with a heat exchanger
able to recover 12,000GJ/year.
Saving: R1.1 million
Estimated Project Cost: R5 million
Payback: 5 years
HFO with energy content 43MJ/kg
HFO cost R4/kg
Site CO2 saving
Based upon an HFO kiln producing 30 million bricks per annum, with an energy
consumption at 5GJ/000, 150,000GJ/year.
Vented Hot Clean Air: 140t CO2/year
Heat Exchanger: 870t CO2/year
6.3.8. Variable Speed/Frequency Drives
Variable Speed/Frequency Drives
Description
Variable Speed (or Frequency) Drives are used to control the flow or pressure
of a fluid to meet demand. In kiln operation, they represent one of the most
effective energy efficiency investments brick manufacturers can make. Not
only do they reduce power consumption by reducing the speed of the motor,
the increased control of airflow and kiln pressure can also result in additional
savings on fuel.
Where fans are used to control air flow or pressure within a kiln (such as the
exhaust, combustion and cooling air), they traditionally use a simple in-line
damper to restrict the flow when required. The control of flow is not very precise
and there is only a small reduction in power consumption, due to the increase
in resistance to flow that the damper has introduced. Replacing the damper
with a variable speed drive enables the speed of the motor and fan impeller to
be precisely controlled, and as no damper is used, the power savings are much
larger. A reduction in fan speed of 10% using a damper, might reduce power
consumption by 5%; using a VSD will reduce it by 25%.
Technology
Maturity
Variable speed drives are a mature, but still developing technology. Their cost
continues to drop, particularly for motor sizes below 500kW, they are now
extremely reliable and last as long as the motor.
VSDs are used as standard by kiln manufacturers for new tunnel kilns and are
widely retro-fitted in tunnel and Hoffman kilns.
VSD and motor
Power savings using a VSD (VFD) compared to damper control for reducing air flow.
10 20 30 40 50 60 70 80 90 1000
0
20
40
60
80
100
Flow Rate (%)Damper VFD
Inpu
t po
wer
(%
)
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201680 81
Variable Speed/Frequency Drives
Project
Approach
Identifying the opportunities to make savings with VFDs is relatively easy:
1. Identify all motors that control flow or pressure.
2. Does the motor have a damper that is used to control flow through the fan?
3. If the fan does not have a damper, would the process benefit from being able
to control the flow?
If the answer to either of the last questions is yes, then a VSD will deliver
process improvements and energy savings. As a rule of thumb, all exhaust fans
deliver savings from a properly controlled VSD. Most combustion air and cooling
fans will as well.
Variable speed drives can be expensive and require space in an air conditioned
switch room or control cabin. Select the two or three motors that will deliver
the highest rate of return rather than simply undertake a blanket installation
programme.
Power savings can be estimated using the graph above or more accurately
using the online saving calculators provided by technology providers. The
business case will be most accurate when the performance curves of the fans
are used along with the measured flows through them.
Fuel savings are usually delivered alongside power reduction and arise from
reducing the amount of excess air forced into the kiln through combustion air
and cooling fans, or removed through the exhaust fan.
Estimated Project
Cost
The costs associated with variable speed drive projects are:
• The cost of VSD;
• The cost of housing the VSD (air conditioned control room required);
• The cost of a new fan (if required);
• The cost of installation (low if done in house).
They vary widely according to the size of the motor, the supplier used and the
terms negotiated.
Some typical costs are:
Installation costs are estimated at 25% of the equipment cost.
motor, kW VSD motor
50 R100,000 R40,000
100 R200,000 R100,000
200 R400,000 R200,000
Energy Management
Description
Energy management is an important aspect of manufacturing management. The
objective is to deliver the highest value to the business for each unit of heat and
power used. In brick making, this means manufacturing saleable products with the
lowest specific energy consumption (SEC) possible.
One of the reasons energy is often forgotten, even in an energy intensive process
like brick making, is that it is often viewed as an uncontrollable fixed cost, rather than
something we can actively control and reduce. Patterns of use and opportunities for
savings are sometimes poorly understood.
For organisations that are used to managing resources such as labour, materials,
output levels and quality, managing energy consumption is a simple transition -
by incorporating it as a controllable variable cost into the production performance
report.
The international standard ISO50001 offers excellent guidance on adopting
energy management and at its heart, is the continuous improvement concept of
understanding use, identifying energy waste or poor performance, planning and
implementing improvements, and verifying the savings achieved as summarised in
the diagram below.
Within a company that has senior management commitment to energy management,
the setting of reduction targets and providing weekly information on how well the
process is performing is one of the most effective methods of delivering short
term energy savings. Shires Bathroom reduced their energy bill by 11% within 12
months of implementing their own Energy Management System.
6.3.9. Energy Management
ENERGYMANAGMENT
CYCLE
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201682 83
Energy Management
Case Study
Shires Bathroom is a medium-sized sanitary ware company in the UK struggling
to compete with the larger producers in the medium priced market sector. Having
successfully increased production and quality to reduce overhead costs per item,
they had seen their energy costs remain high, thus offsetting the savings they were
achieving.
Shires formed an energy management team led by the production director with
improved measurement and reporting at the heart. A weekly performance report
was prepared on the energy consumption for each major process, i.e. casting,
drying, firing and the boiler. The report was reviewed by the process managers and
their teams each week so they could plan changes and measure the improvements,
or otherwise, they delivered. By the end of the first year, they had reduced their
energy consumption by 11%, saving £120,000 in their first year for a £10,000
investment.
Simple Reporting Tool Used
Trend in Kiln Consumption, kWh/t
Air Compressors
Description
Compressed air is an essential utility in many brickworks, but it is a very
expensive one to produce. In fact, nearly 90% of the energy required to compress
air is turned into waste heat,and as a result, compressed air at the point of use
costs around R7/kWh.
Compressors can be powered by electricity or by a diesel engine; the most
common types used are the reciprocating engine and the screw compressor.
Screw compressors tend to be more efficient and better at delivering higher
volumes, while reciprocating engines are capable of achieving higher pressures
and are readily available with diesel power when power is not available at site or
portability is important.
A single 100 kW (70hp) compressor operating 4,000 hours per year will typically
consume R150,000/year. A large percentage of this energy is simple wasted in
one or more of the following ways:
i) System leakage through joints, holes, open valves (a 3mm diameter hole in a system at 7 bar will leak about 11 litres/sec and cost around 20,000 ZAR/year);
ii) Storing compressed air at a higher pressure than is required;
iii) Inefficient sequence management of multiple compressors;
iv) Using warm intake air (it takes more energy to compress warm air);
v) Compressors operating when there is no or little demand (compressors running on standby still consume 40% of the energy they need when operating at full load).
6.3.10. Air Compressors
Screw compressor
Rreciprocating
compressor
Target 7,776Apr-04 13 week average 7,939
Saving/loss for quarter -£1,172production gas actual gas target elec actual elec target variance
w/e date tonnes kWh/tonne kWh/tonne kWh/tonne kWh/tonne £04/04/2004 164 5,757 6,112 760 812 -74011/04/2004 100 9,106 7,787 1,497 1,061 2,28318/04/2004 0 0 0 0 0 025/04/2004 143 6,583 6,656 849 893 -252
TOTAL 408 6,871 6,715 972 902 1,290
4,000
5,000
6,000
7,000
8,000
9,000
10,000
38 1 14 27 40
gas
kWh/
tonn
e
week number
Kiln Savings from Energy Management
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201684 85
Air Compressors
Technology
Maturity
High efficiency screw compressors have been on the market for many years.
They are available with variable speed drives so that output is continually varied
to match demand, thereby delivering more efficient operation when demand is
below the design duty.
Many manufacturers use more than one compressor to meet a variable demand
patterns. Sequencing software is available that enables the most efficient
compressor or combination compressors to be used to meet demand, and
ensures those that are not needed are switched off.
Integrated software is available on a modern compressor that allows the efficiency
of their operation to be monitored on a daily basis and thus improvement action
to be planned.
Project
Approach
Optimising a compressed air system requires a simple systematic approach.
1. Optimise the efficiency of supply
Match the size of your compressor to your demand. If your demand is at a
constant level and stable, a single fixed speed compressor with a standby
compressor is ideal.
If the demand is variable but predictable, a series of fixed speed compressor
controlled by a sequence controller may be the best answer. If demand is
un-predictable, a VSD compressor will be the most cost effective solution.
Always ensure that the intake air is taken from the coldest source available,
usually outside the building.
Generate compressed air at the lowest pressure you need. For every one
bar of pressure you drop, you will save 10%. If you have a small load at high
pressure, consider a dedicated compressor.
2. Improve distribution
Design ring mains to be as short as possible and build in shut off valves for
networks that are infrequently used.
Do not oversize primary and secondary compressed air storage.
Never keep condensate traps fixed open as they leak.
3. Minimise Demand
Operate a leak system check as part of routine maintenance and check for
leaks at least once per month.
Isolate redundant pipework.
Avoid compressed airfor cleaning and only use high efficiency nozzles.
Air Compressors
Saving &
Payback
Example Saving (Electricity)
Assuming a site has two 100kW compressors:
• Each operating 4,000 hours/year;
• Each on standby (off load) 50% of the time;
• System pressure is 8 bar (maximum point of use pressure required 7 bar);
• Leakage levels are at 30% when measured by pressure decay at zero
demand (quite normal for an unmaintained compressed air network).
The cost of running these two compressors is 560,000 kWh/year or R400,000/
year.
Savings (power only)
Site CO2 saving
Two 100kW compressors after system optimisation
270t CO2/year (from electricity)
Grid electricity 1.07 kg CO2/kWh
Best Practice Measure saving kWh/
year
saving ZAR/
year
Controlling leaks to no more than 15% of
demand
84,000 60,000
Reducing supply pressure to 7.2 38,000 27,000
Using a sequencer to reduce off load time
from 50% to 10
128,000 92,000
TOTAL 250,000 179,000Electricity cost R0.72 / kWh
6.4. Energy Management Opportunities (and Reference to Existing Guides)
A number of guides for energy management have
been developed and include the National Business
Initiative document entitled "Energy Management:
A Guide to Controlling Energy Use” (January 2014).
Controlling the impact of rising energy costs and
increased competition is crucial amongst the
risk management objectives of any business. A
systematic approach is needed to ensure that
businesses manage this risk and continually
work towards improving energy performance.
Two approaches exist with regards to efforts to
control energy usage in a business, namely (i)
the energy auditing approach; and (ii) the energy
management approach.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201686 87
These are outlined in the following figures.
The figure above indicates the haphazard approach
to controlling energy costs through ad-hoc energy
audits. Although the energy audit can provide
focus on energy savings opportunities, the lack of a
strategic plan to ensure long-term implementation
of measures to reduce energy consumption results
in lost opportunities. A system approach would
provide ongoing momentum in terms of reducing
energy intensity, and is a holistic approach
ensuring buy-in from the entire staff complement.
This approach is indicated in the following figure.
The Energy Management approach to controlling
energy costs allows for the strategic development
(driven by top management) of an energy
policy which outlines objectives of the Energy
Management System and operating targets
(driven by management representative and Energy
Management team). Through the incorporation
of Energy Management in day-to-day operational
activities, the awareness needed amongst all staff
is facilitated. This ensures Energy Management is
taken into procurement practices (ensuring energy
efficient equipment is purchased and new designs
take cognisance of energy performance) as well
as ultimately creating an energy focus within the
company culture, ensuring sustainability of the
system and continuous improvement.
The following section describes the merits of a
certified ISO50001 Energy Management System.
6.4.1. Relevance of ISO50 001
The Department of Energy has developed
regulations entitled “Registration, reporting
on energy management and submission of
energy management plans”. These regulations
require companies whose total annual energy
consumption exceeds 180TJ (50GWh) to apply to
the Department within 90 days of the regulation
promulgation dateas per provided questionnaire
under Annexure B of the regulation (other format)
as relevant to Brickworks. This data is to be
submitted via the Energy Efficiency Monitoring
System (EEMS) web portal (www.eems.co.za),
covering the following:
• Company details;
• Reporting period;
• Energy consumption, broken down into
different energy carriers (including total energy
use reported in TJ);
• Physical output in terms of production figures
for various products relevant for the same
reporting period for which energy data was
provided;
Figure 23: Energy auditing approach to controlling energy costs
Figure 24: Energy management approach to controlling energy costs
• Economic gross output in terms of millions of
rand.
The energy use data shall be submitted, for the
preceding financial year, to the Department within
90 days of promulgation of the regulations, and
thereafter the data shall be submitted within 60
days of the end of each financial year.
Companies with annual consumption equal to
or exceeding 400TJ (111GWh) need to fulfil
both the reporting requirements outlined above
as well as develop an Energy Management Plan
in accordance with the ISO50001. This plan is
required within 12 months from the promulgation
of the regulations (and renewed plans every five
years thereafter) for which:
• Energy baselines need to be calculated in
accordance with ISO50001;
• Energy efficiency savings potentials ar
identified;
• Energy performance indicators for monitoring
energy performance are developed;
• Reporting on the implementation of the energy
management plans, and achieved energy
savings is carried out (required within 30 days
of the end of each financial year).
Companies commencing operations, and whose
total annual energy consumption is equal to or
exceeds 180TJ after the promulgation of these
regulations, must apply to be registered on the
Energy Efficiency Monitoring System (EEMS)
web portal (www.eems.co.za) within 30 days after
commencement of such operations.
The following table provides an outline of the
brickwork annual production for different product
weights and differing kiln technologies (and hence
energy intensities) for which either the (i) reporting
requirements or (ii) reporting requirements and
Energy Management Plan would be required.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201688 89
Table 15: Production size of different brickworks triggering Energy Management Plans and/or reporting requirements Table16: SANS ISO 50 001 management system roles and responsibilities
Brick Technology
Production of
Bricks (2.6kg) per YearProduction of Bricks (3.2kg) per Year
Reporting
RequirementsEnergy ManagementPlan
Reporting
Requirements
Energy Management Plan
Clamp Kiln
(3.7MJ/kg-brick)19-42 Million ≥ 42 Million 15-34 Million ≥ 34 Million
Clamp Kiln
(3.0MJ/kg-brick)23-51 Million ≥ 51 Million 19-42 Million ≥ 42 Million
Clamp Kiln
(2.4MJ/kg-brick)29-64 Million ≥ 64 Million 23-52 Million ≥ 52 Million
Tunnel Kiln
(2.1MJ/kg-brick)33-73 Million ≥ 73 Million 27-60 Million ≥ 60 Million
Hoffman Kiln
(1.5MJ/kg-brick)46-103 Million ≥ 103 Million 38-83 Million ≥ 83 Million
VSBK
(1MJ/kg-brick)69-154 Million ≥ 154 Million 56-125 Million ≥ 125 Million
The table outlines that only the smaller brickworks
will be exempt from both energy reporting
requirements, while only the large brickworks
will be required to fulfil both the reporting
requirements and Energy Management Plan. The
lower the energy intensity of the brickworks, the
greater the production of bricks allowed before
the requirement of either fulfilment of the Energy
Management Plan and/or reporting requirement.
It is important to note that if the site / company
already has an ISO14001, ISO9001, or
ISO22001 system in place, the Energy
Management System can be built off these
platforms with the extension of the systems to
include the energy relevant aspects as well as
the following additional items not covered in
the clauses of the aforementioned standards:
• Management Responsibility (if related to
ISO14001 standard);
• Development of an Energy Baseline;
• Development of Energy Performance Indicators;
• Documentation Requirements (if related to
ISO14001 standard);
• Design of Facility Energy Efficiency
Requirements (if related to ISO14001
standard);
• Procurement of Energy Efficiency Services,
Products, Equipment and Energy (if related to
ISO14001 standard).
The basic roles and responsibilities of management
and management representative as defined in the
SANS ISO 50 001 standard are highlighted in the
alongside table.
Topic TOP MANAGEMENT MANAGEMENT REPRESENTATIVE
1. Energy Policy
Defining, establishing, implementing,
and maintaining an energy policy
Ensure planning of EnM activities are
designed to support the energy policy
Conducting Management Reviews
Promote awareness of energy policy
and strategic energy objectives on all
levels
2. EnMS
Framework
Identifying scope and boundaries to
be addressed by EnMS
To ensure compliance with the
international standard and is
continuously improved
3. Resources
Providing necessary resources to
establish, implement, maintain and
improve the EnMS and resulting
energy performance
Identify individuals to support the
EnM activities
Appointment of a management
representative and consent to the
formation of an Energy
Management team
Define and communicate
responsibilities and authorities in
order to facilitate effective EnM
4. CommunicationCommunicate the importance of
EnM within the organisation
To report to top management with
respect to energy performance and
the EnMS performance
5. Project
Management and
Monitoring
Ensuring that energy objectives and
targets are set
Determine criteria and methods
necessary to ensure both operation
and control of EnMS are effective
Ensuring that EnPIs are appropriate
for organisation
Considering energy performance in
long-term planning
Ensuring results are measured and
reported at determined levels
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201690 91
Table17: Procedure for development of simplified Energy Management System for small brickworks
For small brickworks not requiring an Energy Management Plan but still wanting to benefit from such a
system, a more simplified version as detailed below could be applied.
Simplified EnM System Format
ENERGY POLICY: Written or electronic declaration of commitment of the management to introduce an alternative system and operate
Signed undertaking
RESOURCES: Energy Management Representative appointed for monitoring and maintenance of energy data collection and assessment
Written appointment of an Energy Management Repre-sentative (may be portion of existing job) with roles and responsibilities
TRACKING ENERGY CONSUMPTION: Traceable documentation of current energy sources and energy use amounts for minimum the last 12 months and, where possible, in recent years
• In physical units (kWh) and the cost (rand)• Percentage of individuals energy users• Data source (measuring system, precision)
Spreadsheet/tracking system
SCOPE AND BOUNDARIES: Detailed corporate statement on applied energy sources, locations
Top management declaration that all energy sources and locations were fully covered
AREAS OF SIGNIFICANT ENERGY USE:• Analysis of energy consumers• Directory/table of installations, equipment, plant components, consumption groups, consumption areas (capacity, performance, year of construction, energy demand)• Information on temperature level and amount of usable waste heat• Documentation of measuring methods and devices
• Description of assessment methods and information on measuring devices• Maintenance Manual, measurement protocols
ENERGY SAVINGS OPPORTUNITY LIST/TARGETS:Determination of potential savings based on the energy review and development of Energy Performance Indicators (EnPIs) e.g.: kWh/kg-brick
List of possible targets (linked to EnPIs, etc.), minutes of meetings
FINANCIAL EVALUATION OF OPPORTUNITIES:Economic evaluation of measures for the use of potential savings calculations
Internal rate of return/net present value/payback peri-od company protocols
IMPLEMENTATION PROGRAMME:Documented energy savings program
Action plan with responsibilities, deadlines and resources
MANAGEMENT REVIEW (CHECKING):Evidence that the management was informed of the results of simplified EnM system
Minutes, signed documentation
RESOLUTIONS FOR SYSTEM/EnPI IMPROVEMENT:Decisions on measures of meetings
Signed action plans
6.5. Industrial SymbiosisDefinition: Industrial symbiosis is the sharing
of services, utility, and by-product resources
among industries in order to add value, reduce
costs and improve the environment. Industrial
symbiosis is a subset of industrial ecology, with a
particular focus on material and energy exchange.
Our current industrial processing and production
are on an unsustainable path of growth and
development. One tool to address sustainability
in industrial activities is industrial symbiosis. This
is a resource efficient approach where unused
or residual resources of one company are used
by another company. Resources could include
material, energy, water, assets, logistics, knowledge,
etc. and this typically results in mutual economic
and environmental benefits.
Some of the benefits that flow from these symbiotic
relationships are:
• A greater diversion of waste disposal to landfill
sites;
• Reduced raw material input costs to recipient
companies;
• Reduced transport footprint for companies
transporting waste to distant landfill sites;
• Reduced energy consumption required for the
conversion of virgin material; and
• Reduced CO2 emission resulting from lower
waste volumes at landfill sites.
Industrial symbiosis uses various tools to
engage with companies. These include business
opportunity workshops, individual company
meetings and company site visits, which help to
ascertain how industrial symbiosis can be beneficial
to participating companies.
In a typical business opportunity / synergy
identification workshop, companies present all
the un-utilised resources they generate, inviting
discussions with those companies interested in
using their waste resources and by-products as
an input in their business processes; synergies will
be created in this manner. An industrial symbiosis
facilitator will capture all the potential synergies
into a management system to follow-up and drive
action. Individual company reports with potential
identified synergies will be generated and sent to
each individual company for further follow ups. The
facilitator assists companies seeking to identify
additional synergies and provides support in the
implementation of these synergies, facilitates
negotiations with companies and provides
technical support.
Figure 25: Schematic of a typical industrial symbiosis network
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201692 93
Early industrial waste symbiosis programmes
failed to generate sufficient interest to sustain the
synergies and symbiotic business relationships
which are key drivers of successful IS programmes.
Central to these failures was the difficulty of
identifying waste opportunities.
Through the use of industrial symbiosis
methodology, it is anticipated that brick
manufacturing facilities are most likely to gain
substantial economic benefit from the use of other
industries waste materials like slag and waste sand.
The case studies that have so far been generated
as explained below indicate how this has been
feasible (Case Study based on UK Scenario).
MJ Allen provides ferrous and nonferrous castings
in the UK and abroad. As with many cast metal
producers, MJ Allen were incurring significant
disposal costs for spent foundry sand from the
metal casting process. While sand was recycled
on site as far as possible, it eventually loses the
properties required for moulds.
MJ Allen’s site in Kent contacted Industrial
Symbiosis in the UK to look for alternative solutions
for nearly 500 tonnes of sand being sent to landfill
every year. After suggesting several industrial
members that could use the sand, it transpired
that one, Hanson Aggregates, were supplying
virgin sand to the foundry. Hanson is one of the
UK’s largest suppliers of construction materials,
and often use recycled materials. Discussions
and investigation began on the take-back solution
for the site.
It was also found that the waste sand is often
suitable for use in asphalt, cement, bricks and
pipe bedding. After discussion and investigations
between MJ Allen and Hanson, it became
clear that by collecting the sand for use as a
recycled aggregate, Hanson could make good
use of a resource otherwise destined for landfill.
Meanwhile, the arrangement would save MJ Allen
over £30,000 a year and help them improve their
environmental performance.
In order to enable sand collections, new pipework
was required and the foundry was happy to invest
the time and money in this infrastructure. Regular
collections are now being made by Hanson who
stockpile the material and process it for use in
asphalt products.
The results that were generated from this
intervention were calculated in terms of CO2
reduction (49 tonnes/year) and cost savings
(£36,546.00/year).
• Landfill diverted: 480 tonnes/year
• Private investment: £3,000
• Virgin materials: 498 tonnes/year
• Water: 18 tonnes equivalent/year
While there are many examples of foundry sand
reuse in construction materials, the potential has
not yet been fully realised in foundries across the
South African market. NCPC-SA - with the current
industrial symbiosis programme in its infancy
stage - is keen to spread the word among its
stakeholders.
6.6. TrainingIt is estimated that there are 300,000 brick kilns
throughout the world man
6.6.1. Green Skills Development Initiatives
of the NCPC-SA
One of the NCPC-SA’s key strategies involves
the development of “green skill-sets” that would
facilitate more resource efficient and cleaner
production (RECP) practices. It is in pursuit of this
objective that the NCPC-SA aims to commission
the development of a number of training
packages, designed to equip RECP Practitioners/
Professionals with specialist skill-sets.
As the implementation partner of UNIDO’s IEE
Project, the NCPC-SA’s recent focus was on training
courses related to energy efficiency, developed
by UNIDO-contracted international experts. The
NCPC-SA also initiated the development of new
RECP training courses. The list of training offerings
include a two-day classroom-based theoretical
workshop, followed by expert training that
combines theory and workplace training over six to
nine months in each of the following disciplines:
• Energy Management System Implementation
• Industrial Energy System Optimisation
o Steam System Optimisation
o Compressed Air System Optimisation
o Fan System Optimisation
o Pump System Optimisation
o Process Heating System optimisation
o Motor System Optimisation
• Resource Efficiency and Cleaner Production
The objectives and learning outcomes of the
respective offerings are as follows:
Energy Management System –two-day End-user Training Programme
Objective: The objective of this two-day training,
targeted at enterprises’ staff responsible for
developing and implementing the Energy
Management System within the company, is to
provide trainees with the knowledge, understanding
and tools that will enable them to initiate the
development and implementation of an EnMS
aligned with ISO 50001.
Learning goals: By the end of the two-day user
training, the trainees will have achieved the
following learning goals:
1. Good understanding of the elements of an
EnMS;
2. Good understanding the benefits of EnMS
and ISO50 001;
3. Ability to put together a high-level project
management plan (time, resources, costs,
etc.) to implement an EnMS within their
organisation;
4. Understanding of the assistance and services
offered by the UNIDO Project and where to
find additional resources and information;
5. Ability to report back to top management on
the EnMS and its benefits;
6. Ability to initiate the development and
implementation of an EnMS.
Energy Management System Implementation - Expert Training Programme
Objective: The objective of the EnMS Expert
Training Programme is to create a cadre of
national experts equipped with the knowledge,
skills and tools needed to support adoption
and implementation in the industry of aligned
Energy Management Systems, which conform to
ISO50 001. This is done by providing technical
assistance to enterprises and coaching of
facility personnel on EnMS development and
implementation. The trained national experts will
then be able to:
1. Promote and sell EnMS and ISO500001 to
industry management;
2. Work with enterprise to establish and
implement EnMS that functions, i.e. deliver
energy performance improvements;
3. Work with enterprise to establish and implement
EnMS that fully conform with ISO50 001;
4. Build EnMS development and implementation
capacity of enterprises’ personnel;
5. Conduct ½ day workshop for factory manager
sand management, raising awareness of the
benefits and costs of implementing an EnMS in
conformance with ISO50 001 and presenting
the range of technical and financial assistance
to be made available by UNIDO Projects;
6. Conduct two-day user training for enterprise
Energy Managers and other relevant personnel
on how to develop and implement an EnMS
aligned with ISO50 001.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201694 95
Learning goals: At the end of the Expert Training
Programme, national trainee/experts shall have
gained the following knowledge, expertise and
skills:
1. Immediate and strategic benefits of EnMS/
ISO50 001 implementation;
2. National legislation and regulation relevant to
the adoption and/or implementation of EnMS
and/or ISO50 001;
3. Financing options available for Energy
Efficiency Projects and EnMS/ISO50 001
implementation;
4. Working understanding of all elements of an
Energy Management System in conformance
with ISO50 001;
5. Working understanding of resource
requirements and costs involved in the
implementation of EnMS/ ISO50 001 in
industry;
6. Ability to apply an EnMSin an industrial facility;
7. Experience in the practical implementation of
an EnMS, including use of supporting tools;
8. Ability to and experience in reviewing an EnMS,
verifying and reporting on energy performance;
9. Ability and experience to effectively deliver ½
day awareness workshop and 2-day training on
energy management system and ISO50 001.
Steam System Optimisation – End-user ProgrammeObjective: The objective for the three days of
steam end-user training is to provide more in-
depth technical information on undertaking an
industrial steam system energy assessment and
making improvements to industrial steam systems.
Additionally, it aims to provide hands-on training for
using all the US DOE steam system Best Practices
software tools in the field while doing an industrial
steam system energy assessment.
Learning goals: At the completion of the three-day
end-user training on SSO, participants will be able to:
1. Use the ASME Steam System Energy
Assessment Standard (ASME-EA-3-2009)
and undertake field work to do the steam
system assessments;
2. Identify gaps and deficiencies in energy
efficiency in industrial steam systems;
3. Ask for specific field data and measurements
required to undertake a steam system
assessment;
4. Develop a model simple steam system project
using fundamental law of physics, thermo-
dynamics and heat transfer;
5. Proficiently use the US DOE Steam Best
Practices software tools (SSST, SSAT and
3EPlus) and/or other resources to evaluate the
steam systems, identify optimisation
opportunities in industrial plants and conduct
an impact – level analysis;
6. Create a preliminary report that summarises
the findings from the steam energy assessment.
Steam System Optimisation – End-user Programme
Objective: The primary objective of the SSO
Experts Training Programme is to create a cadre
of national experts equipped with the knowledge,
skills and tools needed to support adoption and
implementation of steam system optimisation in
industry. The national SSO Experts will provide
technical assistance to enterprises and coach
facility personnel on SSO development and
implementation. The trained national experts will
work with enterprises to establish and implement
SSO that functions, i.e. delivers energy performance
improvements and sustainable best practices.
Learning goals: A further goal of the Expert
Training Programme is to select a smaller
group of national experts (at least four per
country) who will also be equipped with
skills required to promote and “sell” SSO to
industry and build basic SSO development and
implementation capacity of enterprise personnel.
These selected national experts will also:
1. Conduct one-day Basic SSO training on
steam systems assessment, identification of
optimisation measures and implementation of
operational improvements;
2. Conduct two-day Advanced SSO training
on steam systems assessment, identification,
development and implementation of
optimisation measures and projects.
At the completion of the Experts Training on SSO,
in addition to the learning goals mentioned in the
one-day Basic and two-day Advanced training
sections above, participants shall have gained the
knowledge, expertise and skills in the following
areas:
1. Immediate and strategic benefits of
undertaking industrial steam system
assessments;
2. Ability to apply a SSO methodology in an
industrial facility;
3. Working understanding of all elements of an
industrial SSO methodology, including
planning, implementation, performance
checking and review;
4. Working understanding of resource
requirements and cost involved in the SSO
implementation in industry;
5. Experience in practical implementation of
SSO including use of Best Practices tools and
resources;
6. Working and hands-on knowledge of field data,
measurement and verification of potential
benefits, projects complexities, technological
barriers and operational risks that may exist in
industry;
7. Benefits of doing detailed due-diligence on
projects to be implemented from the results of
the industrial steam systems assessments;
8. Working with a vendor and/or service provider
(such as an engineering company) to design,
specify and procure state-of-the-art equipment
that may be required for the SSO project
implementation;
9. Create a case-study level report that
summarises the success of the SSO Project
and which can be disseminated industry-wide
as a testimonial or success story of replication
in similar or other applications;
10. Ability to and experience in reviewing an
existing SSO system, verifying and reporting
on its energy performance;
11. Ability to and experience in effectively
delivering a one-day Basic and two-day
Advanced (in tandem with another national/
international expert) training in SSO (will
apply to only few trainees selected to become
national SSO trainers).
Pump System Optimisation – Two-day End-user ProgrammeObjective: This two-day PSO end-user training is
primarily designed to build enterprise personnel’s
comprehension of and technical capacity for PSO
and to enable them to initiate the development and
implementation of PSO measures and projects. The
training is also intended to raise further enterprises’
interest in the UNIDO technical assistance
offer for complex PSO project implementation.
Learning goals: The participants (facility engineers,
operators and maintenance staff of enterprises,
as well as energy service providers) will recognise
the benefits of PSO, learn how to assess their
pump systems, identify potential optimisation
opportunities, and determine how to achieve cost
savings and energy efficiency through appropriate
application of pumps in new and existing systems,
different control methods and maintenance and
operational best practices. They will also learn
how to make cost calculations and quantitatively
assess pump systems and potential improvement
opportunities, also through the use of software tools
such as the Pump System Assessment Tool (PSAT).
Learning Objectives:
1. Define PSO and LCC;
2. Understand the importance of pump systems
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201696 97
optimisation and the importance of a Life cycle
cost analysis;
3. Perform a group exercise on conducting a PSO
and consider how to pre-screen pump systems;
4. Recognise types of pump systems and
understand the importance of the systems
approach;
5. Understand pump system fluid relationships
and performance curves;
6. Pump equation, affinity laws and pump system
calculations;
7. Recognise the importance of field
measurements and perform a group exercise
on using field measurements;
8. Recognise the benefits of the PSAT software
tool and how it can be used to identify potential
opportunities;
9. Be aware of pump system optimisation
resources and review the next steps they
should take if they are interested in PSO;
10. Understand how to select pump system
optimisation providers and report their take-
away from the training;
11. Understand the PSAT software tool through a
practice example;
12. Outline how to apply best practices to correct
operational and maintenance deficiencies;
13. Correctly apply variable frequency drives and
have basic understanding of the international
Pump Assessment Standard;
14. Identify a template to build a business case
to justify additional resources to implement
optimisation projects, create an action plan for
PSO and report their key take-away from the
training.
Pump System Optimisation - Expert Training ProgrammeObjective:The objective of the PSO Expert Training
Programme is to create a cadre of national experts
equipped with the knowledge, skills and tools
needed to support implementation of PSO in
industry by providing the following services:
1. Technically assisting enterprises and coaching
facility personnel on pump system optimisation
project development and implementation; and
2. Conducting the PSO end-user training on
pump system assessment, identification of
optimisation measures, and development and
implementation of operational improvements.
Learning goals: At the end of the PSO Expert
Training Programme, national trainees / experts
shall have gained the following knowledge,
expertise and skills:
1. In depth understanding of the benefits of pump
system optimisation.
2. Ability to pre-screen pump systems and identify
potential energy saving opportunities;
3. In-depth understanding of pump and system
curves and pump optimisation calculations;
4. Ability to conduct pump system assessments
in accordance with international pump system
assessment standards;
5. Ability to use flow, pressure and power
measurement instrumentation to collect field
data;
6. Having practical experience in using the PSAT
software tool;
7. Ability to determine the most cost effective
pump system improvements and correctly
applying variable frequency drives;
8. Effectively delivering the two-day end-user
training. This goal will apply only to trainees.
Electric Motors Optimisation – Two-dayEnd-user ProgrammeObjective: This two-day MSO end-user training
is primarily designed to build or consolidate
enterprise personnel’s understanding of MSO and
technical capacity for MSO oriented actions and
to enable them to initiate the development and
implementation of MSO measures and projects.
The training is also intended to raise further interest
in the UNIDO training and technical assistance
offers.
Learning goals: The participants will recognise
the benefits of MSO and learn how to qualitatively
assess motor systems and identify potential
optimisation opportunities, and determine how
to achieve cost savings and energy efficiency
through appropriate application of motor in new
and existing systems, different control methods
and maintenance and operational best practices.
The participant will learn how to effectively present
MSO benefits and opportunities to management.
Learning objectives: During the training, the
participants will:
1. Define motor and motor system;
2. Differentiate between motor types;
3. Define motor energy performance and
efficiency, and understand the factors that
influence it;
4. Learn about standards relating to motor
system energy efficiency;
5. Recognise the benefits of MSO;
6. Assess different control methods;
7. Discuss how to conduct MSO;
8. Prioritise enterprise-wide MSO opportunities;
9. Calculate the cost-savings of MSO.
Electric Motors Optimisation - Expert Training ProgrammeObjective: The MSO Expert Training Programme
is an intensive training delivered by leading
international Motor Systems Optimisation (MSO)
experts to national energy efficiency experts,
service providers, equipment vendors and industry
engineers. This training provides more in-depth
technical information on troubleshooting and
making improvements to industrial motor systems.
This training also introduces basic principles for
energy efficient design of motor systems, how
to successfully sell motor systems improvement
projects to management and how to select a motor
system optimisation service provider. National
experts are trained through classroom, on-the-job
and coaching by international MSO experts and
equipped with the expertise, skills and the tools
required for providing the following services:
1. Technical assistance to enterprises and
coaching facility personnel on motor systems
optimisation projects development and
implementation;
2. Conducting two-day MSO training on motor
systems assessment, identification of optimisation
measures, development and implementation of
operational improvements.
Learning goals:The participants (national energy
efficiency experts, service providers, equipment
vendors and industry engineers) will learn how to
assess motor systems and saving opportunities,
evaluate and prioritise optimisation strategies,
gain understandingofmaintenance issues and how
they relate to energy saving, carry out a full MSO
assessment, and work with the partner enterprises
to prepare and implement MSO measures and
investment projects so that they can qualify as
UNIDO MSO Experts and their customers can
achieve energy efficiency and cost savings.
Learning objectives: During the training, the
participants will:
1. Review key concepts relating to motor systems
applications, optimisation and auditing;
2. Examine advanced motor technologies;
3. Review factors affecting motor system
efficiency;
4. Evaluate different control strategies;
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 201698 99
5. Assess power quality and other reliability
issues (voltage levels, voltage unbalance,
harmonics, voltage sags, micro-interruptions
and ride through capabilities);
6. Select appropriate measurement strategies;
7. Screen for motor-based opportunities in fluid
power systems;
8. Systematically screen for the most promising
motor systems for energy savings;
9. Interpret claims for voltage optimisation
products;
10. Quantify and rank optimisation strategies;
11. Report their key take-away from the session;
12. Screen for opportunities;
13. Decide what measurements to take;
14. Take measurements;
15. Analyse results.
Fans system Optimisation – Two-dayEnd-user Programme
Objective: This two-day FSO end-user training is
primarily designed to build enterprise personnel’s
comprehension of and technical capacity for FSO
and enable them to initiate the development and
implementation of FSO measures and projects. The
training is also intended to raise further interest in
the UNIDO technical assistance offer for complex
FSO project implementation.
Learning goals: The participants (facility engineers,
operators and maintenance staff of enterprises,
as well as energy service providers) will recognise
the benefits of FSO and learn how to qualitatively
assess their fan systems and identify potential
optimisation opportunities, determine how to
achieve cost savings and energy efficiency
through appropriate application of fans in new and
existing systems, different control methods and
maintenance and operational best practices. They
will also learn how to make cost calculations and
quantitatively assess fan systems and potential
improvement opportunities, also through the use of
software tools such as the Fan System Assessment
Tool FSAT.
Learning objectives: During the training, the
participants will:
1. Discuss key terms and concepts of FSO;
2. Examine different fan types and control
components;
3. Explain the benefits of FSO;
4. Assess how well each fan system is meeting
the specific enterprise process needs;
5. Calculate the cost of operating fans;
6. Prioritise enterprise-wide system optimisation
opportunities;
7. Assess how well each fan system is meeting
the specific enterprise process needs for
heating/cooling/drying;
8. Calculate the cost of operating fans;
9. Outline how to apply best practices to correct
operational and maintenance deficiencies;
10. Explain the purpose and functions of the FSAT
software;
11. Describe how to use FSAT software for fan
system inputs:
12. Describe how to use FSAT software for fan
system outputs:
13. Practice using FSAT software to complete
FSAT optimisation ratings;
14. Identify a template to build a business case
to justify additional resources to implement
optimisation projects;
15. Create an action plan for FSO;
16. Report their key take-away from the training.
Fan System Optimisation - Expert Training Programme
Objective: The objective of the FSO Expert Training
Programme is to create a cadre of national experts
equipped with the knowledge, skills and tools
needed to support adoption and implementation of
FSO in industry, by providing the following services:
1. Technically assisting enterprises and coaching
facility personnel on Fan System Optimisation
Project development and implementation; and
2. Conducting the two-day FSO end-user
training on fan system assessment,
identification of optimisation measures,
and development and implementation of
operational improvements.
Learning objectives: During the training, the
participants will:
1. Review key concepts related to qualitative and
quantitative assessments of fan systems,
explain terms, concepts and equipment involved
with measuring fan system performance;
2. Discuss ISO measurement standards;
3. Develop a measurement plan based on ISO
standards;
4. Take on-site fan system measurements
according to ISO standards, calculate fan flow
rate and other performance parameters based
on the field data according to ISO standards,
use the performance test results, assess FSO
potential; and report their key take-away from
the session;
5. Develop a list of relevant FSO strategies, review
affinity laws and control strategies and quantify
and rank optimisation strategies;
6. Discuss how to report findings and
recommendations to customers and analyse
how to avoid and troubleshoot fan system
problems;
7. Review duct system design parameters;
8. Apply FSAT to analyse a FSO opportunity and
report their key take-away from the session;
9. Report their FSAT findings;
10. Describe heat recovery opportunities and
strategies;
11. Discuss motor and variable speed drive
selection criteria and application tips;
12. Discuss relevant parameters for fan systems
that transport materials;
13. Review key design parameters for industrial
ventilation systems;
14. Design a new energy efficient fan system;
15. Explain how to prepare FSO projects for
management investment decisions and for
financing and report their key take-away from
the session.
16. Take the final written and oral exam to qualify
as a UNIDO FSO Expert.
Compressed Air System Optimisation – Two-day End-user Programme
Objective: This two-day CASO End User training is
primarily designed to build enterprise personnel’s
comprehension of and technical capacity for CASO
and to enable them to initiate the development and
implementation of CASO measures and projects.
The workshop is also intended to raise further
enterprises’ interest in the UNIDO technical
assistance offer for complex CASO project
implementation.
Learning goals: The participants (facility engineers,
operators and maintenance staff of enterprises, as
well as energy service providers) will recognise the
benefits of CASO and learn how to qualitatively
assess their compressed air systems and identify
potential optimisation opportunities, and determine
how to achieve cost savings and energy efficiency
through appropriate application of compressed
air in new and existing systems, different control
methods and maintenance and operational best
practices. They will also learn quantitatively assess
compressed air systems and potential improvement
opportunities.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016100 101
Learning objectives: During the training, the
participants will:
1. Discuss key terms and concepts of compressed
air systems;
2. Explain the types of compressors;
3. Examine different component types and the
system design;
4. Explain the importance of condensation in the
compressed air system;
5. Assess how well each system component
is meeting the specific enterprise quality
requirements;
6. Calculate the cost of operating the compressed
air system;
7. Prioritise enterprise-wide system optimisation
opportunities;
8. Identify system design factors
9. Identify caso opportunities and evaluate an
existing system;
10. Design a demand profile;
11. Calculate the cost of operating a compressed
air system;
12. Outline how to apply best practices to correct
operational and maintenance deficiencies;
13. Report their key take-away from the workshop.
Compressed Air system optimisation -Expert Training Programme
Objective:The objective of the CASO Expert
Training Programme is to create a cadre of
national experts, equipped with the knowledge,
skills and tools needed to support adoption and
implementation of CASO in industry by providing
the following services:
1. Technically assisting enterprises and
coaching facility personnel on compressed air
system optimisation project development and
implementation; and
2. Conducting the two-day CASO end-user
workshop on compressed air system assessment,
identification of optimisation measures, and
development and implementation of operational
improvements.
Learning goals: The participants (national energy
efficiency experts, service providers, equipment
vendors and industry engineers) will learn how
to measure compressed air systems and assess
CASO opportunities, evaluate and prioritise
optimisation strategies, troubleshoot compressed
air system problems, design energy efficient
compressed air systems, carry out a full CASO
assessment, and work with the partner enterprises
to prepare CASO investment projects so that they
can qualify as UNIDO CASO Experts and their
customers can achieve energy efficiency and cost
savings.
The participants will become comfortable with the
training philosophy and adult learning principles
that form the basis for the CASO end-user training
format and methodology so that they can effectively
facilitate the training in the future. They will also
learn how to effectively coach different personality
types in CASO projects.
Learning objectives: The Standards of Knowledge
isa list of the prerequisite knowledge that is needed
to pass the UNIDO Compressed Air System Expert
certification exam.
1. Definitions and gas laws associated with
compressed air systems;
2. Understand compressors and components of
the compressed air system;
3. General operating principles and types of
positive displacement and dynamic
compressors;
4. Understanding pressure drops;
5. Understanding Air Treatment;
6. Determine proper storage requirements;
7. Identify the sources of demand and evaluate
their appropriateness;
8. Quantify the impact of variations in the
compressed air supply on plant production;
9. Establish a baseline of system performance;
10. Develop a pressure profile;
11. Identify the sources of demand, including; 1)
system applications, 2) critical flow applications,
and 3) leak load;
12. Calculate energy costs associated with various
components of the system;
13. Calculate lifecycle costs of components;
14. Compressed air quality requirements;
15. Estimate the cost impact of poor air quality on
production;
16. Take measurements to document the dynamics
of the system;
17. Recommend changes that will improve system
performance and reduce operating costs.
RECP Two-day End-user Training
Objective: This is a theoretical course with no
practical or fieldwork involved. Upon successful
completion of this course, participants will:
1. Understand why RECP is an important initiative;
2. Understand the evolution of the RECP
Programme;
3. Understand the major steps in conducting a
RECP Assessment;
a. Preparation for undertaking an RECP
Assessment;
b. Collecting Data for RECP analysis;
c. Reviewing the data captured and determining
trends and problems;
d. Generating RECP solution options;
e. Undertaking feasibility assessment for RECP
interventions;
f. Implementing RECP interventions;
g. Institutionalising RECP interventions through
controlling and improvement;
4. Understand the content and process of a pre
assessment;
5. Understand how to identify and prioritise
detailed assessment focus areas;
6. Know which user-friendly RECP software is
available;
7. Know which RECP metrics are important;
8. Be eligible to attend the Advanced RECP
Course.
Resource Efficiency and Cleaner Production Expert Training
Objective: This is a practical course with
significant amounts of practical or fieldwork
involved. On successful completion of this course,
participants will:
1. Have reviewed the pertinent contents of the
RECP Basic Course;
2. Have completed a variety of case study
discussions illustrating the various aspects of
the RECP process;
3. Have undertaken an assisted RECP pre-
assessment;
4. Have undertaken a comprehensive RECP
assessment of their host plant and made
suitable recommendations;
a. Have prepared for undertaking an RECP
Assessment;
b. Have collected data for RECP analysis
c. Have reviewed the data captured and
determined trends and problem;
d. Have generated RECP solution options;
e. Undertaking feasibility assessment for REC
interventions;
f. Have implemented RECP interventions;
g. Institutionalise RECP interventions through
controlling and improvement;
5. Be able to undertake a pre-assessment;
6. Be able to use user-friendly RECP software
and RECP metrics.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016102 103
Given the outputs and findings of the project, a number of next steps are planned in 2016 and 2017 as
part of the ongoing EECB work with the brick sector. These include:
• Release of the guidelines through the CBA website;
• Availability for industry to access the thermal energy tool through the CBA website (could include
training to brick companies of the tool);
• Release of funding calls for a series of best practice demonstrations by the EECB in early 2016 for
completion by the end of 2016;
• Dissemination of the findings of the demonstrations in 2017, including case studies, events and
other support;
• A report in 2016 highlighting the available funding mechanisms available for the best practice
identified in these guidelines, such as bank debt, project financing, government schemes, 12L tax
incentives, etc.
Further communication around these activities will come from the EECB and the CBA.
7. Next Steps 8. Appendices
8.1. WorkshopsThrough the project, two workshops were held
in October 2015 to present the findings of the
project. Participants were asked to:
1) Prioritise the list of energy saving opportunities
and choose their top five;
2) Discuss the selected opportunities in groups, in
order to understand:
o What makes this best practice a good
idea?
o What are the key barriers?
o Have you deployed this already and if so,
what was your experience?
Feedback from participants from both workshops
are summarised below.
8.1.1. Pretoria Workshop
26 people, including 13 brick companies, attended
the Pretoria Workshop on the 28th of October
2015. The workshop covered the international
brick sector energy benchmarks, a presentation
of the Thermal Energy Calculator, a discussion
of best practices, and a presentation of current
EECB activities. Participants’ inputs during the
best practices discussion are presented below.
1) Top three opportunities selected by participants
in each of the five groups of best practices.
Group Ranking Opportunity
A
(combustion &
heating efficiency)
1Use of best quality coal available locally with consistent calorific value and
consistent particle size consistent with firing system in place.
2Addition of internal fuel (carbon) to minimise the amount of external firing of solid
fuel required.
3Carry out ongoing daily checks on kiln burners to ensure complete combustion
at point of entry.
B
(brick temperature;
excess air; structural
losses)
1Ensuring bricks leaving the kiln are cooled to below 100oC and the heat is
recovered into the kiln or dryer.
2 Reduce exhaust fan speed to reduce heat loss through exhaust.
3
Improve cooling zone balance by reducing the flow through the exit contravec
and the injection cooling by 10% to reduce the egress of hot air from the cooling
zone into the firing zone. Use PID controller of air movement fans to maintain a
constant pressure in the cooling zone and any heat recovery offtake.
C
(upgrading kiln; heat
recovery; energy
management)
1Use of hot air from the kiln cooling systems as preheated combustion air, for
example roof space and kiln car cooling air.
2Replace the current clamp kiln with a fixed kiln of some kind (e.g. VSBK, Zig-Zag,
TVA, Tunnel Kiln etc.).
3Use of recent model forklifts and optimisation of product movement. Business
case on two old machines replaced by one new machine.
D
(brick moisture; kiln
cars; wastage; alter-
native materials)
1Ensure bricks are fully dried (below 2% moisture content) prior to entering the
kiln.
2Maintaining kiln car seals in optimum condition through planned or condition-
based maintenance.
3 Improvement of souring practice after mining through stockpiling practices.
E
(power)
1Power factor correction to reduce maximum demand charges and resistance
losses.
2 Optimising compressed air system efficiency.
3Convert air movement fan motors to variable speed type or fit separate variable
speed drive (VSD).
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016104 105
2) Feedback from group discussions on eight of the selected opportunities above.
Why is it a good idea? Key barriers Experience
Addition of internal fuel (carbon) to minimise the amount of external firing of solid fuel required
• Cheaper
• External firing requirements
reduced
• Aesthetics
• Availability
• Variability of product output
• Works well
Improvement of souring practice after mining through stockpiling practices
• Improves workability of clay
(extrudability)
• Maturing the clay improves
the consistency of in quality of
the product eventually
• Working capital
• Planning to avoid stock outs
• Limited availability
• Moisture content variations
• Improves extrudability
Reducing temperature of bricks leaving the kiln to below 100oC
• Not wasting energy
• Better handling
• Better quality of product
• Length of kiln
• Kiln cars
• Money
• Material
• Experienced listed benefits
Reduce exhaust fan speed to reduce heat loss through exhaust
• No wasted thermal energy
• No wasted electricity
• Cost of VSDs • Too long to settle
Use of best quality coal available locally with consistent calorific value and consistent particle size
• Closer and therefore cheaper
• Better quality = less coal
burnt
• Consistent Cv = less adjust-
ment
• Transport costs / availability vs
distance
• Availability of small nut starter coal
• Stick with your supplier
Replace the current Clamp Kiln with a fixed kiln of some kind
• Reduction in production cost
• Quality improvement
• Energy efficiency improve-
ment
• Waste reduction
• Reduction in labour
• High initial capital expenditure
• Technical know-how
• Product type/cost/selling
• No
Ensure bricks are fully dried prior to entering the kiln
• Savings on fuel
• Better push rate
• Quality improvement
• Much less waste
• Cash flow
• Infrastructure
• Stock on hand
• Experienced listed benefits
Optimising compressed air system efficiency
• Compressed air is expensive
• Rapid payback
• Training/awareness of stall
• Continuous process
• Include in maintenance schedules
• Do repetitively
• Training = savings
Figure 26: Presentation at Pretoria Workshop
Figure 27: Survey presentation at Pretoria’s Workshop
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016106 107
8.1.2. Cape Town Workshop
16 people, including nine brick companies,
attended the Cape Town Workshop on the 29th
October 2015, which covered the international
Brick sector energy benchmarks, a presentation
of the Thermal Energy Calculator, a discussion
of best practices, and a presentation of current
EECB activities. Participants’ inputs during the best
practices discussion are presented below.
1) Top three opportunities selected by participants
in each of the five groups of best practices.
Group Ranking Opportunity
A
(combustion &
heating efficiency)
1
Use of best quality coal available locally with consistent calorific value and
consistent particle size consistent with firing system in place.
2
Increasing perforation size of extruded bricks consistent with local standards
to reduce firing energy requirement and improve air flow through brick setting.
3
Addition of internal fuel (carbon) to minimise the amount of external firing of
solid fuel required.
B
(brick temperature;
excess air; struc-
tural losses)
1
Ensuring bricks leaving the kiln are cooled to below 100oC and the heat is
recovered into the kiln or dryer.
2
Insulation of hot air pipework & ductwork. In general maintain hot air ductwork
insulation levels to a minimum of 50mm for temperatures below 200oC and
100mm at higher temperatures.
2Ensuring all kiln walls and roofs are maintained in good condition and well
insulated.
C
(upgrading kiln;
heat recovery; en-
ergy management)
1
Process optimisation: operate at higher throughputs at the kiln and higher
operational equipment effectiveness.
1Rip next mining area at conclusion of mining campaign to allow natural forces
(wind, rain and sun) to break down materials before mining.
1
Use of recent model forklifts and optimisation of product movement. Business
case on two old machines replaced by one new machine.
D
(brick moisture;
kiln cars; wastage;
alternative
materials)
1Ensure bricks are fully dried (below 2% moisture content) prior to entering the
kiln.
1 Improvement of souring practice after mining through stockpiling practices.
2
Reduce the thermal mass of kiln car decks using lightweight refractory or fibre.
E
(power)
1 Motor efficiency retrofits on less efficient motors, for example from IEE1 to IEE3.
1Tariff optimisation through shifting operations outside of peak hours, especially
during the high demand season.
1Convert air movement fan motors to variable speed type or fit separate variable
speed drive (VSD).
2) Feedback from group discussions on eight of the selected opportunities above.
Why is it a good idea? Key barriers Experience
Rip new mining area earlier to allow weathering, and improvement of souring practice after mining through stockpiling
practices
• Less green waste
• Higher quality clay
• Better extruding
• Better quality bricks
• Higher % perforations
• Cost of mining and storage
(cash tied up on raw material)
• Need large storage (weather-
ing)
• Remix stockpile
• A lot of brick yards are
using advanced mining and
stockpiling
Reducing temperature of bricks leaving the kiln to below 100oC and heat is recovered into the kiln/dryer
• Energy conservation in kiln/dryer • Infrastructure expense
• Technology restrictions
• Save costs
• Improve profits
Ensure bricks are fully dried prior to entering the kiln
• Improve burning
• Less waste
• Wet brick have higher shrinkage
• Less firing energy
• If over-dry, costly
• Packing of wet bricks – labour
issue
• Reduce breakages
Use of best quality coal with consistent calorific value and particle size
• Consistency
• Combustion control
• Yields
• Availability
• Price
• Better yields
• Quality
• Control
Increase perforation size
• Reduce weight
• Reduce fuel consumption
• Improve drying time
• Delivery costs
• Breakage – new prep plant
• Market resistance
• Not suitable for all technologies
• Improving burning
• Reduce fuel consumption
Motor efficiency retrofits on less efficient motors
• Only as replacement motor • Too long return on investment • No
Convert air movement fan motors to variable speed type or fit separate VSD
• Fault finding
• Reduce energy cost
• Control improvement
• Lower maintenance on moving parts
• Reduce number of parts and leakage
• Cost of VSD
• Skilled labour
• Additional cooling
• Yes
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016108 109
8.2. Common Energy Calculations
There are many different measurements of energy
out there, which can be confusing. KWh, MJ, kcal,
and BTU are all in common use in various markets
and sometimes, comparing apples with apples can
be tricky. Additionally, sometimes energy efficiency
measurements are presented which look good at
first glance, but are they really? Without getting too
complex, this section will present some common
energy calculation norms in South Africa as well
as illustrate some common pitfalls in energy
calculations.
8.2.1. Specific Energy Consumption
A universal norm in energy calculations is SEC or
Specific Energy Consumption. In South Africa, the
most common unit of measurement for SEC is MJ/
kg of fired, saleable product. The importance of the
bold typeface words is illustrated in the following
example:
A tunnel kiln operator and a clamp kiln operator
want to compare their energy consumption. From
his oil consumption, the tunnel kiln operator
believes that his plant is using 2MJ/kg. Similarly,
from the amount of coal duff added into the raw
material, the clamp producer believes that his plant
is using 3.5MJ/kg. Hence, at face value, it appears
as if the tunnel kiln operator is only using 57% of
the energy that the clamp kiln producer uses. Is
this correct?
Please note that the above figures are from actual, operational plants. Undoubtedly, there are plants
doing better (or worse) than the numbers presented above. However, the real numbers are intended to
act as a guide towards reducing confusion for those less familiar with energy calculations.
From the above table, the initial conclusion that the tunnel kiln uses 57% of the energy of the clamp kiln
is shown to be flawed. After including waste and the actual weight of the brick, the tunnel kiln is shown
to have an SEC <49% of the clamp operator’s SEC. If one considers that tunnel kiln technology usually
includes dryers and that no allowance is made above for the true cost of open air drying or hack lines
(diesel, labour, wastage etc.), the true picture moves even further away from the 57% initially considered.
Table 18: Example of calculation of the SEC of a tunnel kiln and a clamp kiln
Measurement Tunnel kiln Clamp kiln Units
Energy consumption 2 3.5 MJ/kg
% of clamp kiln energy 57.1% 100.0%
Waste 6% 20%
Brick weight 2.2 3.2 kg
Annual output 30,000,000 30,000,000 bricks / annum
Annual brick weight output 66,000,000 96,000,000 kg
Annual energy consumption 132,000,000 336,000,000 MJ
Annual waste kg 3,960,000 19,200,000 kg
Annual weight of saleable product 62,040,000 76,800,000 kg
SEC 2.13 4.38 MJ/kg of fired, saleable ware
% of clamp kiln SEC 48.6% 100.0%
8.2.2. Typical Energy Figures for Common South African Kilns
Table 19: Typical energy figures for common South African kilns
Kiln type SEC (MJ/kg) GJ/1000 BEs Brick weight (kg) Dryers
Clamps 3.55 11 3.1 No
Transverse arch 3.50 8.75 2.5 Yes
Tunnel kiln 2.27 5 2.2 Yes
VSBK 1.00 2.6 2.6 No
8.2.3. Useful Conversion Factors
Table 20: Some energy conversion factors
Megajoule 1 MJ = 947.8169879 BTU British Thermal Unit
Megajoule 1 MJ = 238845.9 Cal Calorie
Megajoule 1 MJ = 238.8459 kcal Kilocalorie
Megajoule 1 MJ = 1000 kJ Kilojoule
Megajoule 1 MJ = 0.2777778 kWh Kilowatt hour
Gigajoule 1 GJ = 1000 MJ Megajoule
British Thermal Unit 1 BTU = 0.001055056 MJ Megajoule
British Thermal Unit 1 BTU = 1.055056 kJ Kilojoule
Kilocalorie 1 kcal = 0.0041868 MJ Megajoule
Kilocalorie 1 kcal = 4.1868 kJ Kilojoule
Kilowatt hour 1 kWh = 3600 kJ Kilojoule
Kilowatt hour 1 kWh = 3.6 MJ Megajoule
8.3. Description of Kiln Technologies
Like inother parts of the world, South Africa uses
a number of different types of kiln for the firing
of clay bricks. The kiln types are group into the
following categories:
Continuous Kilns:
• Tunnel kilns
• Vertical shaft brick kiln
• Continuous chamber & annular kilns, e.g.
Hoffman, Bulls Trench Kiln & Zigzag
Intermittent Kilns
• Clamp kiln
• Chamber/shuttle kiln
8.3.1. Continuous Kilns
Continuous kilns are kilns from which continuous
production is possible, i.e. a process in which bricks
are continuously being added and removed.
a) Tunnel kilnA tunnel kiln is a long heated chamber though
which clay bricks are transported usually on trucks
known as kiln cars.
The temperature is kept constant within each
section of the kiln and as the bricks move though
they are heated and cooled at the required rate.
The use of multiple burners in the firing zone of the
kiln and the control of air movement into and out
of the kiln makes accurate temperature control of
each part of the kiln possible and thus the bricks
manufactured are of a high and consistent quality.
The degree of combustion and temperature control
makes it possible to change the temperature and
atmosphere control within the tunnel kiln so that
different products from different clay types can be
manufactured within a tunnel kiln. Tunnel kilns are
capable of high production rates of over 1 million/
week and are normally automated,with a low labour
requirement to operate. Tunnel kilns can utilise
coal, oil and gas as fuels, with all kiln the control
of combustion and temperature is easier with gas
and oil than solid fuels such as coal and bio-mass.
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016110 111
Tunnel kilns are very energy efficient as the cold air used for cooling the bricks can be recovered for
use within the kiln itself or dry bricks by directed the hot air to a separate drying chamber. A simplified
schematic of the process and of the heating profile within the kiln are shown in figure 28.
In South Africa, the kiln technology is the second
most commonly deployed. Worldwide, tunnel kilns
are used to produce top quality facing bricks and
by virtue of the process control that their design
enables. Tunnel kilns can supply ‘waste’ heat
for drying purposes which generally means that
drying is mechanised and independent of weather
conditions.
Figure 28: Tunnel kiln schematic 1
Figure 30: Tunnel kiln
Figure 29: Tunnel kiln schematic 2
b) Vertical Shaft Brick Kiln
The principle of a Vertical Shaft Brick Kiln (VSBK)
is very similar to the tunnel kiln in that they enable
continuous production via the continuous adding
and removal of bricks to the kiln. They are, in
effect, a vertical tunnel kiln but there are a number
of differences. In general a VSBK relies on the
combustion of coal added between the layers of
bricks although they can also be fired with gas or
oil burners.
It has lower control of the air flow within the
kiln than a tunnel kiln and it relies on gravity to
move the bricks through the kiln. The control of
combustion relies of the skilful placement of fuel
within the brick setting, as the bricks are stacked at
the kiln entrance and via the control of air entering
and leaving the kiln.
As a vertical kiln the VSBK acts as a chimney has
a high natural draught meaning that an exhaust
fan is not necessary as with a tunnel kiln, this is
a considerable advantage when electricity is
Tunnel kiln technology is also much better suited
to automation, can produce higher quality products
and generally has health and safety advantages
over most of the simpler alternatives.
Nevertheless, tunnel kiln technology requires large
capital investment, typically 10 – 20 times more
than simpler technologies (Greentech Knowledge
Solutions, New Delhi, 2012).
not available or is unreliable. VSBKs are shorter
(measured from bottom to top) than tunnel kilns
(measured from end to end) as bricks in the lower
layers have to withstand the weight of all the bricks
above, even so a higher incidence of mechanical
damage is to be expected. The relative short length
of the VSBK also means that heating rates and
cooling rates are higher and this increases the risk
of cracking during these phases of the firing cycle.
VSBKs are capable of being very efficient
especially if a skilled operator controls air flow
into the kiln, through the setting and out of the
exhaust. The thick permanent walls can be well
insulated minimising heat losses through them.
The independence of a power supply is also a
great advantage.
A schematic of a VSBK is shown in figure 31. For
high production rates, a number of VSBK would
be required as alone they cannot achieve the high
outputs of tunnel kilns.
Chimney
Natural Gas
To drying house
Outside air
Drying airFlue gasses
preheating section firing section cooling section
1 000 - 1 200 c
75c
Carttransport
Brick load
Tunnelkiln cart
Temperature
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016112 113
Figure 31: Vertical Shaft Brick Kiln (VSBK) schematic Figure 32: Bulls Trench Kiln schematic
c) Continuous and Annular Chamber Kilns
Continuous Chamber and Annular Kilns are the third
type of continuous kiln. Whereas tunnel and VSBK
rely on a constant temperature profile through the
structure with the bricks passing through it, bricks
in continuous chamber and annular kilns remain
stationary and the temperature moves around the
kiln. Whilst a number of chambers are cooling the
hot air from these is providing combustion air for
the chambers that are in their firing phase, the
hots gases from these chambers then move on to
preheat dry bricks. In this way the heat of firing is
recuperated enabling these kilns to be thermally
efficient even though each chamber is being fired
as an intermittent chamber. Continuous chamber
kilns are normally fired using solid fuel, either
incorporated into the brick setting or via ports in
the roof at the appropriate time in the schedule.
Control of air flow is provided via a chimney, usually
of sufficient height to provide sufficient draught
for a number of interlinked chambers, alternatively
fans can be used to control airflow but require a
reliable power supply.
Continuous chamber kilns can vary in size greatly
and are capable of the same levels of output as
tunnel kilns.
There are number of variations of continuous
chamber or annular kilns the main ones are
summarised below.
• Bull’s Trench Kiln (BTK)
There are two main types of Bull’s Trench Kiln –
fixed chimney (FCBTK) and movable chimney
(MCBTK).The moveable chimney provides less
control over air movement and consequently is less
efficient and causes higher pollution levels. The
kiln is one annular chamber with bricks added and
removed at the cold ends of the process as shown
in the diagram.
• Hoffman Kiln
Hoffman Kilns are similar to the BTK design in that
the bricks are set within a large annular chamber.
The main differences are that the individual
chambers can be separated using permanent brick
wall and that all the chambers are connected via
a central flue leading to a fixed chimney. Hoffman
kilns also have a permanent roof through which
fuel can be added to the firing zone, giving further
control over the combustion process that fires the
bricks.
• Zig-ZagKiln
A Zig-zag kiln is a variation of the Hoffman kiln, in
that the stacking of the bricks follows a Zig-Zag
pattern - in effect lengthening the route the air
takes through the setting tacking, thus helping with
combustion and heat recuperation. While some
utilise a natural draft, others use a fan to draw the
fire and heat through the Zig-Zag stacking pattern.
This firing process requires a set of highly trained
and skilled workers to operate and maintain the
kiln.
Figure 33: Hoffman kiln schematic Figure 34: Zig-Zag kiln schematic
COVERED VENTILATION OPENING
TILED ROOF
ENTRANCEFOR LOADING
LOADINGRAMP
GREEN BRICKSSPACES FORSUPPOR BARS
FIRING SHAFT
SINGLE THICKNESS
FIRE BRICKS
PULLEY CHAINBLOCK
SUPPORTINGBARS
BRICK TROLLEY
TROLLEY RAILS
FIRING
ZONE
4 LAYERS 1 BATCH
CENTRAL
INS
ULA
TIO
N F
ILL
INS
ULA
TIO
N F
ILL
SOIL ANDRUBBLEINFILL
FIRED BRICKS
CROSSSECTION
CHIMNEY
ROOF
FLUES
STOKEHOLES
DAMPEROPEN
DAMPERCLOSED
FIRING CHAMBER
SLOTS FORCHAMBER
SEPARATORPLATES
STOKING HOLES
FLUE DAMPERS2
3
4 56
7
8
9
1011
12
ENTRANCE
FIRING CHAMBER
CHAMBER
FLUES
PLAN
ENTRANCE
South Africa Clay Brick Sector Energy Efficiency Guide, 2016South Africa Clay Brick Sector Energy Efficiency Guide, 2016114 115
Most operators examining their kiln during the
firing will be able to assess where the key heat
losses are using the heat balance, and determine
an accurate, specific energy consumption for their
kiln. Nevertheless there are some instruments that
are widely available, easy to use and extremely
useful in improving the perfomance of a kiln. These
are thermocuples for measuring temperatures,
bullers rings for measuring the peak temperature
throughout the firing, and a combustion analyser
for measuring the oxygen and carbon monoxide
(CO) content of exhaust gases. Coupled with this,
should be a record keeping system that measures
the overall “quality” of each firing and thus
promotes the continual improvement of quality
and lower energy costs. Based on these accurate
measurments, plant managers can identify a
number of relevant best practices for their kiln in
the long list of opportunities in Chapter 6.
8.3.2. Intermittent Kilns
a) Chamber & Shuttle Kilns
Chamber kilns are enclosed structures within
which bricks are heated and cooled. They operate
alone as a batch process and as a result much of
the heat is wasted through the exhaust even when
deploying heat recovery technology in the exhaust
stack or through the use of recuperative burners.
Chamber kilns can utilise any type of fuel and can
operate under natural draught or forced draught.
Chamber kilns are much cheaper to than tunnel
kilns and easier to operate and maintain but are
less thermally efficient as there is little to no heat
recovery from the hot gases. Improvements in
thermal efficiency can be made by incorporating
suitable fuel into the brick body recipe and by
linking the exhaust flues of multiple chambers
together so that the hot air exhausted during
cooling can be used within the other chambers.
b) Clamp Kiln
Clamp kiln is a term used for a wide variety of
rudimentary kilns that use solid fuels, such as coal,
either contained within the brick or laid between
layers of bricks. The bricks are stacked with spaces
and channels so that combustion air can reach
the fuel, as well as for exhaust gases to leave the
clamp. The clamp may either have permanent walls
to contain the bricks or be covered with reject
bricks and an outer layer of clay or plaster.
Firing of a clamp requires a great deal of experience
and because of the relatively uncontrolled burning
than takes place, the quality and size of the fired
bricks can vary greatly. Product waste levels are
high, as are pollution levels for the workforce and
the wider environment. Clamp kilns can be more
efficient than chamber kilns, due to their greater
size and the common practice of incorporating fuel
into the body recipe.
Clamps do not require a permanent structure,
making them extremely versatile and easy to install
and maintain.
CADDET. 1993. Insulated carts for tunnel kilns
in brick manufacture. Centre for the Analysis
and Dissemination of Demonstrated Energy
Technologies. Sittard, The Netherlands.
Vicente de Paulo Nicolau & Alessandro Pedro
Dadam. 2009. Numerical and experimental
thermal analysis of a tunnel kiln used in ceramic
production. J. Braz. Soc. Mech. Sci. & Eng. vol. 31
No. 4 Rio de Janeiro Oct/Dec 2009.
Sameer Maithel, R Uma, Anil Kumar and N
Vasudevan. 1999. Energy Conservation and
Pollution Control in Brick Kilns. Tata Energy
Research Institute, Habitat Place, Lodhi Road, New
Delhi -110 003.
Sakkti Sustainable Energy Foundation. 2012. A
Roadmap for Cleaner Brick Production in India.
Sakkti Sustainable Energy Foundation.
Environment, Climate Change, and Water
Resources Unit. 2011. Report No. 60155-BD
Introducing Energy-efficient Clean Technologies in
the Brick Sector of Bangladesh.
Swiss Agency for Development and Cooperation.
Energy efficiency of different kilns. Available from
http://www.poverty.ch/asian-brick-industry/
energy-efficient-kiln.html. Accessed on 07/07/15.
Figure 35: Intermittent Chamber kiln. Figure 36: Clamp kiln schematic
9. References
United Nations Industrial Development
Organisation (UNIDO). 2010. Global Industrial
Energy Efficiency Benchmarking.
Carbon Trust. CTG043 Industrial Energy Efficiency
Accelerator Guide to the Brick Sector. 2012. The
United Kingdom.
The International Energy Agency (IEA). 2007.
Energy Indicators Report, Tracking Industrial Energy
Efficiency & CO2 Emissions.
Clean Air Task Force. 2010. Carbon Black From
Brick Kilns. Available from http://www.catf.us/
resources/presentations/files/Black_Carbon_
from_Brick_Kilns.pdf
Accessed on 07/07/15.
World Bank & ESMAP: Environment, Climate
Change, and Water Resources Unit, South Asia
Region. 2011. Introducing Energy-efficient Clean
Technologies in the Brick Sector of Bangladesh.
Vertical Shaft Brick Kiln (VSBK)
An effective South-South Technology
Transfer for climate change mitigation in the
Clay Brick sector. Paper for the 16th IUAPPA World
Clean Air Congress. Authors: Luca De Giovanetti
([email protected]). John Volsteedt
SWISSCONTACT
Swisscontact ¦ Swiss Foundation for Technical
Cooperation
107 Nicolson Street, Brooklyn Office Park,
Pretoria - South Africa
Tel. +27 (0) 12 346 5102
www.swisscontact.org
THE CARBON TRUST
Registered in England and Wales
Reg. Number 04190230
Registered at 4th Floor Dorset House
27-45 Stamford Street
London SE1 9NT
Tel. +44 (0)20 7170 7000
CLAY BRICK ASSOCIATION OF SOUTH AFRICA
P O Box 1284
Halfway House
1685
South Africa
Tel. +27 (0)11 805-4206
www.claybrick.org/energy-efficiency-guidelines
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